C. Geibel

Publication List Details

Period

1980 - 2009

Number

633

Co-Authors

Pressure-induced change of the pairing symmetry in superconducting CeCu2Si2 (2009)

Lengyel, E., Nicklas, M., Jeevan, H. S., Sparn, G., Geibel, C., Steglich, F., ...

Low-temperature (T) heat-capacity measurements under hydrostatic pressure of up to p=2.1 GPa have been performed on single-crystalline CeCu2Si2. A broad superconducting (SC) region exists in the T-p...

Quantum Griffiths phase in CePd(1-x)Rh(x) with x ~ 0.8 (2009)

Brando, M., Westerkamp, T., Deppe, M., Gegenwart, P., Geibel, C., Steglich, F.

The magnetic field dependence of the magnetisation ($M$) and the temperature dependence of the ac susceptibility ($\chi' = dM/dH$) of CePd(1-x)Rh(x) single crystals with $0.80 \leq x \leq 0.86$ are...

$H - T$ phase diagram of YbCo$_{2}$Si$_{2}$ with $H // $[100] (2009)

Pedrero, L., Brando, M., Klingner, C., Krellner, C., Geibel, C., Steglich, F.

We report on the first high-resolution dc-magnetisation ($M$) measurements on a single crystal of \ycs. $M$ was measured down to 0.05 K and in fields up to 12 T, with the magnetic field $H$ parallel...

Development of the critical exponent at the antiferromagnetic phase transition of YbRh2Si2 under chemical pressure (2009)

Krellner, C., Klingner, C., Geibel, C., Steglich, F.

We present specific-heat measurements in the vicinity of the antiferromagnetic phase transition on single crystals of the alloy Yb(Rh_{1-x}Co_x)2Si2 for x

Single Crystal 31P NMR Studies of the Frustrated Square Lattice Compound Pb2(VO)(PO4)2 (2009)

Nath, R., Furukawa, Y., Borsa, F., Kaul, E. E., Baenitz, M., Geibel, C., ...

The static and dynamic properties of V^{4+} spins (S = 1/2) in the frustrated square lattice compound Pb2(VO)(PO4)2 were investigated by means of magnetic susceptibility chi and 31P nuclear magnetic...

Rare earth magnetism in CeFeAsO: A single crystal study (2009)

Jesche, A., Krellner, C., De Souza, M., Lang, M., Geibel, C.

Single crystals of CeFeAsO, large enough to study the anisotropy of the magnetic properties, were grown by an optimized Sn-flux technique. The high quality of our single crystals is apparent from the...

Spin correlations and exchange in square lattice frustrated ferromagnets (2009)

Skoulatos, M., Goff, J. P., Geibel, C., Kaul, E. E., Nath, R., Shannon, N., ...

The J1-J2 model on a square lattice exhibits a rich variety of different forms of magnetic order that depend sensitively on the ratio of exchange constants J2/J1. We use bulk magnetometry and...

Magnetic properties of PrPd$_{2}$Si$_{2}$ and PrPt$_{2}$Si$_{2}$ (2009)

Anand, V. K., Hossain, Z., Geibel, C.

We have investigated the two rare-earth intermetallic compounds PrPd$_{2}$Si$_{2}$ and PrPt$_{2}$Si$_{2}$ by means of magnetization, electrical resistivity and heat capacity measurements. While...

Magnetocrystalline anisotropy and antiferromagnetic phase transition in PrRh$_{2}$Si$_{2}$ (2009)

Anand, V K, Hossain, Z, Behr, G, Chen, G, Nicklas, M, Geibel, C

We present magnetic and transport properties of PrRh$_{2}$Si$_{2}$ single crystals which exhibit antiferromagnetic order below T$_{N}$ = 68 K. Well defined anomalies due to magnetic phase transition...

Low temperature properties of the Electron Spin Resonance in YbRh2Si2 (2009)

Sichelschmidt, J., Kambe, T., Fazlishanov, I., Zakharov, D., Wykhoff, J., ...

We present the field and temperature behavior of the narrow Electron Spin Resonance (ESR) response in YbRh2Si2 well below the single ion Kondo temperature. The ESR g factor reflects a Kondo-like...

Magnetic field dependence of the antiferromagnetic phase transitions in Co-doped YbRh_2Si_2 (2009)

Klingner, C., Krellner, C., Geibel, C.

We present first specific-heat data of the alloy Yb(Rh_(1-x)Co_x)_2Si_2 at intermediate Co-contents x=0.18, 0.27, and 0.68. The results already point to a complex magnetic phase diagram as a function...

Why could Electron Spin Resonance be observed in a heavy fermion Kondo lattice? (2009)

Kochelaev, B. I., Belov, S. I., Skvortsova, A. M., Kutuzov, A. S., Sichelschmidt, J., Wykhoff, J., ...

We develop a theoretical basis for understanding the spin relaxation processes in Kondo lattice systems with heavy fermions as experimentally observed by electron spin resonance (ESR). The Kondo...

Electrical resistivity ofYb(Rh1-xCox)2Si2 single crystals at low temperatures (2009)

Friedemann, S., Oeschler, N., Krellner, C., Geibel, C., Steglich, F.

We report low-temperature measurements of the electrical resistivity of Yb(Rh1-xCox)2Si2 single crystals with 0

Magnetization study on the field-induced quantum critical point in YbRh_2Si_2 (2009)

Tokiwa, Y., Geibel, C., Steglich, F., Gegenwart, P.

We study the field-induced quantum critical point (QCP) in YbRh$_2$Si$_2$ by low-temperature magnetization, $M(T)$, and magnetic Gr\"uneisen ratio, $\Gamma_{\rm mag}$, measurements and compare the...

Kondo-Cluster-Glass State near a Ferromagnetic Quantum Phase Transition (2009)

Westerkamp, T., Deppe, M., Kuechler, R., Brando, M., Geibel, C., Gegenwart, P., ...

We report on a comprehensive study of CePd$_{1-x}$Rh$_x$ $(0.6 \leq x \leq 0.95)$ poly- and single crystals close to the ferromagnetic instability by means of low-temperature ac susceptibility,...

Heavy fermion behavior in PrRh2B2C: Excitonic mass enhancement (2009)

Anand, V. K., Hossain, Z., Chen, G., Nicklas, M., Geibel, C.

We report magnetic and transport properties of a new quaternary borocarbide PrRh$_{2}$B$_{2}$C, based on magnetisation, resistivity and specific heat studies. This compound forms in...

Fluctuations and correlations in a frustrated S=1/2 square lattice with competing ferromagnetic and antiferromagnetic interactions: a muSR study (2009)

Carretta, P., Filibian, M., Nath, R., Geibel, C., King, P. J. C.

Zero and longitudinal field $\mu$SR measurements in Pb$_2$VO(PO$_4$)$_2$ and BaCdVO(PO$_4$)$_2$, two prototypes of the frustrated $S=1/2$ square lattice model with competing ferromagnetic and...

Violation of critical universality at the antiferromagnetic phase transition of YbRh2Si2 (2009)

Krellner, C., Hartmann, S., Pikul, A., Oeschler, N., Donath, J. G., Geibel, C., ...

We report on precise low-temperature specific-heat measurements, C(T), of YbRh2Si2 in the vicinity of the antiferromagnetic phase transition on a single crystal of superior quality (RRR 150). We...

Hybridization Phenomena in Nearly-Half-Filled f-Shell Electron Systems: Photoemission Study of EuNi2P2 (2009)

Danzenbächer, S., Vyalikh, D. V., Kucherenko, Y., Kade, A., Laubschat, C., Caroca-Canales, N., ...

The mixed-valent compound EuNi2P2 was studied by photoemission. Observed splittings and dispersions of the Eu 4f(6) final state close to energy crossings of the Eu 4f and Ni 3d states are explained...

Interplay between superconductivity and magnetism in K-doped EuFe2As2 (2008)

Paulose, P. L., Jeevan, H. S., Geibel, C., Hossain, Z.

Superconductivity is found in 50% K-doped EuFe2As2 sample below 33 K. Our results of electrical resistivity, magnetic susceptibility and 57Fe and 151Eu Mossbauer spectroscopy provide clear evidence...

Magnetic susceptibility of YbRh2Si2 and YbIr2Si2 on the basis of a localized 4f electron approach (2008)

Kutuzov, A. S., Skvortsova, A. M., Belov, S. I., Sichelschmidt, J., Wykhoff, J., Eremin, I., ...

We consider the local properties of the Yb3+ ion in the crystal electric field in the Kondo lattice compounds YbRh2Si2 and YbIr2Si2. On this basis we have calculated the magnetic susceptibility...

Effect of pressure and Ir substitution in YbRh2Si2 (2008)

Macovei, M. E., Nicklas, M., Krellner, C., Geibel, C., Steglich, F.

In this article we present a study of the electrical resistivity of Yb(Rh-xIrx)2Si2, x=0.06, under high pressure and in magnetic field. Ir substitution is expanding the unit cell and leads to a...

Magnetic behaviour of PrPd2B2C (2008)

Anand, V. K., Chaudhuri, A., Dhar, S. K., Geibel, C., Hossain, Z.

We have synthesized a new quaternary borocarbide PrPd$_{2}$B$_{2}$C and measured its magnetization, electrical resistivity and specific heat. The compound crystallizes in the LuNi$_{2}$B$_{2}$C-type...

Divergence of the Magnetic Gr\"{u}neisen Ratio at the Field-Induced Quantum Critical Point in YbRh$_2$Si$_2$ (2008)

Tokiwa, Y., Radu, T., Gegenwart, P., Geibel, C., Steglich, F.

The heavy fermion compound YbRh$_2$Si$_2$ is studied by low-temperature magnetization $M(T)$ and specific-heat $C(T)$ measurements at magnetic fields close to the quantum critical point ($H_c=0.06$...

Magnetic order in Pr2Pd3Ge5 and possible heavy fermion behavior in Pr2Rh3Ge5 (2008)

Anand, V. K., Hossain, Z., Geibel, C.

We report our results on two new ternary intermetallic compounds Pr$_{2}$Pd$_{3}$Ge$_{5}$ and Pr$_{2}$Rh$_{3}$Ge$_{5}$ based on magnetic susceptibility, magnetization, specific heat, resistivity and...

Possible re-entrant superconductivity in EuFe2As2 under pressure (2008)

Miclea, C. F., Nicklas, M., Jeevan, H. S., Kasinathan, D., Hossain, Z., Rosner, H., ...

We studied the temperature-pressure phase diagram of EuFe2As2 by measurements of the electrical resistivity. The antiferromagnetic spin-density-wave transition at T_0 associated with the FeAs-layers...

Interplay between 3d and 4f magnetism in CeCoPO (2008)

Krellner, C., Burkhardt, U., Geibel, C.

The ground state properties of CeCoPO, a homologue of the new high temperature superconductors RFePnO1-xFx, were studied by means of susceptibility, specific heat, and resistivity measurements on...

Effect of pressure on the magnetostructural transition in SrFe2As2 (2008)

Kumar, M., Nicklas, M., Jesche, A., Caroca-Canales, N., Schmitt, M., Hanfland, M., ...

We present a systematic pressure study of poly- and single crystalline SrFe2As2 by electrical resistivity and X-ray diffraction measurements. SrFe2As2 exhibits a structural phase transition from a...

Low-temperature thermopower study of YbRh2Si2 (2008)

Hartmann, S., Oeschler, N., Krellner, C., Geibel, C., Steglich, F.

The heavy-fermion compound YbRh2Si2 exhibits an antiferromagnetic (AFM) phase transition at an extremely low temperature of TN = 70 mK. Upon applying a tiny magnetic field of Bc = 60 mT the AFM...

High-Temperature Superconductivity in Eu0.5K0.5Fe2As2 (2008)

Jeevan, H. S., Hossain, Z., Kasinathan, Deepa, Rosner, Helge, Geibel, C., Gegenwart, P.

Subsequent to our recent report of SDW type transition at 190 K and antiferromagnetic order below 20 K in EuFe2As2, we have studied the effect of K-doping on the SDW transition at high temperature...

Columnar magnetic structure coupled with orthorhombic distortion in the antiferromagnetic iron arsenide SrFe$_2$As$_2$ (2008)

Kaneko, K., Hoser, A., Caroca-Canales, N., Jesche, A., Krellner, C., Stockert, O., ...

Neutron powder diffraction experiments were carried out on polycrystalline SrFe$_2$As$_2$ in order to determine the magnetic structure and its relationship with the crystallographic one. Below...

Superconductivity in SrFe_(2-x)Co_xAs_2: Internal Doping of the Iron Arsenide Layers (2008)

Leithe-Jasper, A., Schnelle, W., Geibel, C., Rosner, H.

In the electron doped compounds SrFe_(2-x)Co_xAs_2 superconductivity with T_c up to 20 K is observed for 0.2 < x < 0.4. Results of structure determination, magnetic susceptibility, electrical...

Strong coupling between magnetic and structural order parameters in SrFe2As2 (2008)

Jesche, A., Caroca-Canales, N., Rosner, H., Borrmann, H., Ormeci, A., Kasinathan, D., ...

X-ray and Neutron diffraction as well as muon spin relaxation and M\"ossbauer experiments performed on SrFe$_2$As$_2$ polycrystalls confirm a sharp first order transition at $T_0 = 205$,K...

Electrical Resistivity and Specific Heat of EuFe2As2 Single Crystals: Magnetic homologue of SrFe2As2 (2008)

Jeevan, H. S., Hossain, Z., Kasinathan, Deepa, Rosner, H., Geibel, C., Gegenwart, P.

We have grown single crystals of EuFe2As2 and investigated its electrical transport and thermodynamic properties. Electrical resistivity and specific heat measurements clearly establish the intrinsic...

Magnetic and structural transitions in layered FeAs systems: AFe2As2 versus RFeAsO compounds (2008)

Krellner, C., Caroca-Canales, N., Jesche, A., Rosner, H., Ormeci, A., Geibel, C.

Resistivity, specific heat and magnetic susceptibility measurements performed on SrFe2As2 samples evidence a behavior very similar to that observed in LaFeAsO and BaFe2As2 with the difference that...

Strong frustration due to competing ferromagnetic and antiferromagnetic interactions: magnetic properties of M(VO)2(PO4)2 (M = Ca and Sr) (2008)

Nath, R., Tsirlin, A. A., Kaul, E. E., Baenitz, M., Büttgen, N., Geibel, C., ...

We present a detailed investigation of the magnetic properties of complex vanadium phosphates M(VO)2(PO4)2 (M = Ca, Sr) by means of magnetization, specific heat, 31P NMR measurements, and band...

Evolution of the Kondo state of YbRh2Si2 probed by high field ESR (2008)

Schaufuß, U., Kataev, V., Zvyagin, A. A., Büchner, B., Sichelschmidt, J., Wykhoff, J., ...

An electron spin resonance (ESR) study of the heavy fermion compound YbRh2Si2 for fields up to ~ 8 T reveals a strongly anisotropic signal below the single ion Kondo temperature T_K ~ 25 K. A...

CeFePO: A Heavy Fermion Metal with Ferromagnetic Correlations (2008)

Brüning, E. M., Krellner, C., Baenitz, M., Jesche, A., Steglich, F., Geibel, C.

The ground state properties of CeFePO, a homologue of the new high temperature superconductors RFePnO(1-x)Fx, were studied by means of susceptibility, specific heat, resistivity, and NMR measurements...

Electronic and magnetic properties of K$_{2}$CuP$_{2}$O$_{7}$ - a model S=1/2 Heisenberg chain system (2008)

Nath, R., Kasinathan, Deepa, Rosner, H., Baenitz, M., Geibel, C.

The electronic and magnetic properties of K$_{2}$CuP$_{2}$O$_{7}$ were investigated by means of susceptibility, specific heat and $^{31}$P nuclear magnetic resonance (NMR) measurements and by LDA...

Hall effect measurements on YbRh2Si2 in the light of electronic structure calculations (2008)

Friedemann, S., Oeschler, N., Wirth, S., Krellner, C., Geibel, C., Steglich, F., ...

Comprehensive temperature-dependent Hall effect measurements on YbRh2Si2, YbIr2Si2 and LuRh2Si2 single crystals are analyzed using theoretical results based on electronic band structure calculations....

Magnetic properties of BaCdVO(PO_4)_2: a strongly frustrated spin-1/2 square lattice close to the quantum critical regime (2008)

Nath, R., Tsirlin, A. A., Rosner, H., Geibel, C.

We report magnetization and specific heat measurements on polycrystalline samples of BaCdVO(PO_4)_2 and show that this compound is a S=1/2 frustrated square lattice with ferromagnetic...

(fl=350mJ/molK (2007)

J. Diehl, S. Klimm, H. Davideit, E. Baur, S. Horn, U. Klinger, ...

We have performed magnetoresistance and Hall effect measurements on ternary Yb-based heavy fermion compounds: YbCu 4 X (X=Ag, Au and Pd) and YbNiAl

a (2007)

D. Ehm, F. Reinert, S. Schmidt, G. Nicolay, J. Kroha, O. Trovarelli, ...

By use of high-resolution photoelectron spectroscopy we investigate the 4f spectral function of the heavy fermion compound CeRu 2 Si 2 in the energy range close to the Fermi level. A normalization...

Single crystal growth and anisotropy of CeRuPO (2007)

Krellner, C., Geibel, C.

We report on the single crystal growth of the ferromagnetic Kondo lattice system CeRuPO using a Sn flux method. Magnetic susceptibility and electrical resistivity measurements indicate strong...

ESR of YbRh2Si2 and 174YbRh2Si2 : local and itinerant properties (2007)

Wykhoff, J., Sichelschmidt, J., Lapertot, G., Knebel, G., Flouquet, J., Fazlishanov, I. I., ...

Below the Kondo temperature the heavy Fermion compound YbRh$_{2}$Si$_{2}$ shows a well defined Electron Spin Resonance (ESR) with local Yb$^{3+}$ properties. We report a detailed analysis of the ESR...

CeRuPO: A rare example of a Ferromagnetic Kondo lattice (2007)

Krellner, C., Kini, N. S., Bruning, E. M., Koch, K., Rosner, H., Nicklas, M., ...

We have determined the physical ground state properties of the compounds CeRuPO and CeOsPO by means of magnetic susceptibility chi(T), specific heat C(T), electrical resistivity rho(T), and...

Structure and transport in multi-orbital Kondo systems (2007)

Kroha, J., Kirchner, S., Sellier, G., W"olfle, P., Ehm, D., Reinert, F., ...

We consider Kondo impurity systems with multiple local orbitals, such as rare earth ions in a metallic host or multi--level quantum dots coupled to metallic leads. It is shown that the multiplet...

High Resolution Photoemission Study on Low-T_K Ce Systems: Kondo Resonance, Crystal Field Structures, and their Temperature Dependence (2007)

Ehm, D., H"ufner, S., Reinert, F., Kroha, J., W"olfle, P., Stockert, O., ...

We present a high-resolution photoemission study on the strongly correlated Ce-compounds CeCu_6, CeCu_2Si_2, CeRu_2Si_2, CeNi_2Ge_2, and CeSi_2. Using a normalization procedure based on a division by...

Quantum phase transition in the heavy-fermion compound YbIr$_2$Si$_2$ (2006)

Yuan, H. Q., Nicklas, M., Hossain, Z., Geibel, C., Steglich, F.

We investigate the pressure-temperature phase diagram of YbIr$_2$Si$_2$ by measuring the electrical resistivity $\rho(T)$. In contrast to the widely investigated YbRh$_2$Si$_2$, YbIr$_2$Si$_2$ is a...

Spin dynamics of $Yb Rh_2 Si_2$ observed by Electron Spin Resonance (2006)

Sichelschmidt, J., Wykhoff, J., Ferstl, J., Geibel, C., Steglich, F.

Below the Kondo temperature $T_{\rm K}$ electron spin resonance (ESR) usually is not observable from the Kondo-ion itself because the characteristic spin fluctuation energy results in a huge width of...

Observation of an optical non-Fermi-liquid behavior in the heavy fermion state of YbRh$_{2}$Si$_{2}$ (2006)

Kimura, S., Sichelschmidt, J., Ferstl, J., Krellner, C., Geibel, C., Steglich, F.

We report far-infrared optical properties of YbRh$_{2}$Si$_{2}$ for photon energies down to 2 meV and temperatures 0.4 -- 300 K. In the coherent heavy quasiparticle state, a linear dependence of the...

Quantum criticality in the cubic heavy-fermion system CeIn_{3-x}Sn_x (2006)

Kuechler, R., Gegenwart, P., Custers, J., Stockert, O., Caroca-Canales, N., Geibel, C., ...

We report a comprehensive study of CeIn$_{3-x}$Sn$_x$ $(0.55 \leq x \leq 0.8)$ single crystals close to the antiferromagnetic (AF) quantum critical point (QCP) at $x_c\approx 0.67$ by means of the...

Multiple energy scales at a quantum critical point (2006)

Gegenwart, P., Westerkamp, T., Krellner, C., Tokiwa, Y., Paschen, S., Geibel, C., ...

We report thermodynamic measurements in a magnetic-field-driven quantum critical point of a heavy fermion metal, YbRh$_2$Si$_2$. The data provide evidence for an energy scale in the equilibrium...

Quantum Criticality in doped CePd_1-xRh_x Ferromagnet (2006)

Sereni, J. G., Westerkamp, T., Kuechler, R., Caroca-Canales, N., Gegenwart, P., Geibel, C.

CePd_1-xRh_x alloys exhibit a continuous evolution from ferromagnetism (T_C= 6.5 K) at x = 0 to a mixed valence (MV) state at x = 1. We have performed a detailed investigation on the suppression of...

Quasiquartet CEF ground state with possible quadrupolar ordering in the tetragonal compound YbRu$_{2}$Ge$_{2}$ (2005)

Jeevan, H. S., Hossain, Z., Geibel, C.

e have investigated the magnetic properties of YbRu$_{2}$Ge$_{2}$ by means of magnetic susceptibility $\chi$(T), specific heat C(T) and electrical resistivity $\rho$(T) measurements performed on flux...

Non-Fermi liquid states in the pressurized $CeCu_2(Si_{1-x}Ge_x)_2$ system: two critical points (2005)

Yuan, H. Q., Grosche, F. M., Deppe, M., Sparn, G., Geibel, C., Steglich, F.

In the archetypal strongly correlated electron superconductor CeCu$_2$Si$_2$ and its Ge-substituted alloys CeCu$_2$(Si$_{1-x}$Ge$_{x}$)$_2$ two quantum phase transitions -- one magnetic and one of so...

Anisotropy, disorder, and superconductivity in CeCu2Si2 under high pressure (2005)

Holmes, A. T., Jaccard, D., Jeevan, H. S., Geibel, C., Ishikawa, M.

Resistivity measurements were carried out up to 8 GPa on single crystal and polycrystalline samples of CeCu2Si2 from differing sources in the homogeneity range. The anisotropic response to current...

Field-induced suppression of the heavy-fermion state in YbRh_2Si_2 (2005)

Tokiwa, Y., Gegenwart, P., Radu, T., Ferstl, J., Sparn, G., Geibel, C., ...

We report DC magnetization measurements on YbRh_2Si_2 at temperatures down to 0.04K, magnetic fields B

Ferromagnetic quantum critical fluctuations in YbRh_2(Si_{0.95}Ge_{0.05})_2 (2005)

Gegenwart, P., Custers, J., Tokiwa, Y., Geibel, C., Steglich, F.

The bulk magnetic susceptibility $\chi(T,B)$ of YbRh$_2$(Si$_{0.95}$Ge$_{0.05}$)$_2$ has been investigated %by ac-and dc-magnetometry at low temperatures and close to the field-induced quantum...

Hall-effect evolution across a heavy-fermion quantum critical point (2004)

Paschen, S., Luhmann, T., Wirth, S., Gegenwart, P., Trovarelli, O., Geibel, C., ...

A quantum critical point (QCP) develops in a material at absolute zero when a new form of order smoothly emerges in its ground state. QCPs are of great current interest because of their singular...

Scaling of the magnetic entropy and magnetization in YbRh_2(Si_{0.95}Ge_{0.05})_2 (2004)

Gegenwart, P., Tokiwa, Y., Neumaier, K., Geibel, C., Steglich, F.

The magnetic entropy of YbRh_2(Si_{0.95}Ge_{0.05})_2 is derived from low-temperature ($T\geq 18$ mK) specific heat measurements. Upon field-tuning the system to its antiferromagnetic quantum critical...

Effect of Hydrostatic Pressure on the Kondo Effect in the Heavy Fermion System Yb$_2$Fe$_3$Si$_5$ (2003)

Singh, Yogesh, Ramakrishnan, S., Geibel, C.

We report the effect of hydrostatic pressure on the resistivity of the heavy fermion Kondo lattice compound Yb$_2$Fe$_3$Si$_5$ in the temperature range 2-300 K and in pressures upto 10 Kbar. At...

Exotic superconductivity in the coexistent phase of antiferromagnetism and superconductivity in CeCu2(Si0.98Ge0.02)2: A Cu-NQR study under hydrostatic pressure (2003)

Kawasaki, Y., Ishida, K., Kawasaki, S., Mito, T., Kitaoka, Y., ...

We report a pressure ($P$) effect on CeCu$_2$(Si$_{0.98}$Ge$_{0.02}$)$_2$ where an antiferromagnetic (AFM) order at $T_N \sim$ 0.75 K coexists with superconductivity below $T_c \sim$ 0.4 K\@. At...

Divergence of the Grueneisen Ratio at Quantum Critical Points in Heavy Fermion Metals (2003)

Kuechler, R., Oeschler, N., Gegenwart, P., Cichorek, T., Neumaier, K., Tegus, O., ...

We present low-temperature volume thermal expansion, $\beta$, and specific heat, $C$, measurements on high-quality single crystals of CeNi2Ge2 and YbRh2(Si$_{0.95}$Ge$_{0.05}$)$_2$ which are located...

The break up of heavy electrons at a quantum critical point (2003)

Custers, J., Gegenwart, P., Wilhelm, H., Neumaier, K., Tokiwa, Y., Trovarelli, O., ...

The point at absolute zero where matter becomes unstable to new forms of order is called a quantum critical point (QCP). The quantum fluctuations between order and disorder that develop at this point...

Low temperature magnetic phase diagram of the cubic non-Fermi liquid system CeIn_(3-x)Sn_x (2003)

Pedrazzini, P., Berisso, M. Gomez, Sereni, J. G., Caroca-canales, N., Deppe, M., Geibel, C.

In this paper we report a comprehensive study of the magnetic susceptibility (\chi), resistivity (\rho), and specific heat (C_P), down to 0.5 K of the cubic CeIn_(3-x)Sn_x alloy. The ground state of...

Tuning Heavy Fermion Systems into Quantum Criticality by Magnetic Field (2003)

Gegenwart, P., Custers, J., Tayama, T., Tenya, K., Geibel, C., Sparn, G., ...

We discuss a series of thermodynamic, magnetic and electrical transport experiments on the two heavy fermion compounds CeNi2Ge2 and YbRh2Si2 in which magnetic fields, B, are used to tune the systems...

Antiferromagnetic ordering in the Kondo lattice system Yb$_2$Fe$_3$Si$_5$ (2003)

Singh, Yogesh, Ramakrishnan, S., Hossain, Z., Geibel, C.

Compounds belonging to the R$_2$Fe$_3$Si$_5$ series exhibit unusual superconducting and magnetic properties. Although a number of studies have been made on the first reentrant antiferromagnet...

Exotic magnetism and superconductivity in Ge-substituted CeCu2Si2: A Cu NQR study (2002)

Kawasaki,Y., Ishida,K., Obinata,K., Tabuchi,K., Kashima,K., Kitaoka,Y., ...

We report Cu NQR results on Ge-doped heavy-fermion superconductors CeCu2(Si1-xGex)(2) (0< x≦0.2) and compare with previous results on Ce0.99Cu2.02Si2 (x=0). Once only 1% Ge is substituted for Si to...

Study of Ce(Rh1-xPdx)2Si2: pronounced differences between the CeRh2Si2 and CePd2Si2 ground states (2002)

Berisso,M. G., Pedrazzini,P., Sereni,J. G., Trovarelli,O., Geibel,C., Steglich,F.

We present electrical resistivity and specific heat measurements of alloys on the Rh rich side of the phase diagram of the Ce(Rh1-xPdx)(2)Si-2 system. We compare these results with those obtained at...

An unconventional metallic state in YbRh2(Si1-xGex)2 - a high pressure study (2002)

Mederle,S., Borth,R., Geibel,C., Grosche,F. M., Sparn,G., Trovarelli,O., ...

We present a detailed pressure study of the electrical resistivity p(T) and the specific heat C(T) of the non-Fermi- liquid (NFL) compound YbRh2Si2, and of p(T) for a single crystal in which 5 at.%...

Structure and magnetic order of the Heusler compound Co2NbSn (2002)

Wolter,A. U. B., Bosse,A., Baabe,D., Maksimov,I., Mienert,D., Klauss,H. H., ...

We present a detailed study of the structural and magnetic phase transitions of the Heusler compound Co2NbSn. This material undergoes a structural transition at T-S=235 K from the cubic Heusler Fm3m...

Magnetic transition in the Kondo lattice system CeRhSn2 (2002)

Hossain,Z., Gupta,L. C., Geibel,C.

We present the results of our measurements of magnetization, heat capacity, resistivity and magnetoresistance on the Ce- based intermetallic compound CeRhSn2. The magnetic transition, as reported...

Magnetic Transition in the Kondo Lattice System CeRhSn2 (2002)

Hossain, Z., Gupta, L. C., Geibel, C.

Our resistivity, magnetoresistance, magnetization and specific heat data provide unambiguous evidence that CeRhSn2 is a Kondo lattice system which undergoes magnetic transition below 4 K.

Sr2V3O9 and Ba2V3O9: quasi one-dimensional spin-systems with an anomalous low temperature susceptibility (2002)

Kaul, E. E., Rosner, H., Yushankhai, V., Sichelschmidt, J., Shpanchenko, R. V., Geibel, C.

The magnetic behaviour of the low-dimensional Vanadium-oxides Sr2V3O9 and Ba2V3O9 was investigated by means of magnetic susceptibility and specific heat measurements. In both compounds, the results...

YbRh2Si2: Spin Fluctuations in the Vicinity of a Quantum Critical Point at Low Magnetic Field (2002)

Ishida,K., Okamoto,K., Kawasaki,Y., Kitaoka,Y., Trovarelli,O., Geibel,C., ...

We report a Si-29 NMR study on aligned single crystals of YbRh2Si2 which shows behavior characteristic of a quantum critical point (QCP: T-N-->0). The Knight shift K and the nuclear spin-lattice...

Magnetic-Field Induced Quantum Critical Point in YbRh2Si2 (2002)

Gegenwart,P., Custers,J., Geibel,C., Neumaier,K., Tayama,T., Tenya,K., ...

We report low-temperature calorimetric, magnetic, and resistivity measurements on the antiferromagnetic (AF) heavy- fermion metal YbRh2Si2 ( T-N=70 mK) as a function of magnetic field B. While for...

Antiferromagnetic transition in CePd2B2C and possible heavy- fermion behaviour in CePt2B2C (2002)

Hossain,Z., Geibel,C., Gupta,L. C., Nagarajan,R., Godart,C.

Our measurements of the magnetic susceptibility, resistivity and specific heat of CePd2B2C, a quaternary borocarbide, show clearly that Ce is in a stable trivalent state in this compound and orders...

Divergence of the Heavy Quasiparticle Mass at the Antiferromagnetic Quantum Critical Point in YbRh_2Si_2 (2002)

Gegenwart, P., Custers, J., Tayama, T., Tenya, K., Geibel, C., Trovarelli, O., ...

We report low temperature specific heat, C, magnetization, M, susceptibility, chi, and electrical resistivity, rho, measurements on high-quality single crystals of the heavy-fermion system...

Spin dynamics in a structurally ordered non-Fermi liquid compound: YbRh_2Si_2 (2002)

Ishida, K., MacLaughlin, D. E., Bernal, O. O., Heffner, R. H., Nieuwenhuys, G. J., Trovarelli, O., ...

Muon spin relaxation (muSR) experiments have been carried out at low temperatures in the non-Fermi-liquid heavy-fermion compound YbRh_2Si_2. The longitudinal-field muSR relaxation function is...

Spin-Triplet Superconductivity in UNi2Al3 Revealed by the 27Al Knightshift Measurement (2002)

Ishida,K., Ozaki,D., Kamatsuka,T., Tou,H., Kyogaku,M., Kitaoka,Y., ...

We report Al-27 Knight shift (K-27) measurement on a single- crystal UNi2Al3 that reveals a coexistence of superconductivity and a spin-density-wave (SDW) type of magnetic ordering (T- SDW=4.5 K )....

Antiferromagnetic ordering in the Kondo lattice system Yb2Fe3Si5 (2002)

Singh,Y., Ramakrishnan,S., Hossain,Z., Geibel,C.

Compounds belonging to the R2Fe3Si5 series exhibit unusual superconducting and magnetic properties. Although a number of studies have been made on the first reentrant antiferromagnet superconductor...

Composition dependence of the magnetic properties of Ge-doped CeCu2Si2 (2002)

Berisso,M. G., Pedrazzini,P., Deppe,M., Trovarelli,O., Geibel,C., Sereni,J. G.

Due to the proximity of CeCu2Si2 to a quantum critical point, the ground state of this compound is extremely sensitive to sample preparation conditions. Small excess of one component can lead to...

Magnetic-Field Induced Quantum Critical Point in YbRh$_2$Si$_2$ (2002)

Gegenwart, P., Custers, J., Geibel, C., Neumaier, K., Tayama, T., Tenya, K., ...

We report low-temperature calorimetric, magnetic and resistivity measurements on the antiferromagnetic (AF) heavy-fermion metal YbRh$_2$Si$_2$ (${T_N =}$ 70 mK) as a function of magnetic field $B$....

Coexistence of antiferromagnetism and superconductivity in heavy-fermion systems (2002)

Kitaoka,Y., Kawasaki,Y., Mito,T., Kawasaki,S., Zheng,G. Q., Ishida,K., ...

We report the novel pressure (P)-temperature (T) phase diagrams of antiferromagnetism (AFM) and superconductivity (SC) in CeRhIn5, CeIn3, and CeCu2Si2 revealed by the nuclear quadrupole resonance...

Evidence for the Coexistence of Superconductivity and the Magnetic A-Phase in CeCu2Si2 proved by Muon Knight Shift (2002)

Koda,A., Higemoto,W., Kadono,R., Kawasaki,Y., Ishida,K., Kitaoka,Y., ...

Muon spin rotation measurements under high transverse fields (HTF-ASR) have been performed on polycrystalline samples of Ce0.99Cu2.02Si2. The muon hyperfine coupling constant was determined to be...

Magnetic history effects in the Heusler compound Co2NbSn (2002)

Wolter,A. U. B., Klauss,H. H., Litterst,F. J., Geibel,C., Süllow,S.

The magnetic properties of the Heusler compound Co2NbSn have been investigated. Whereas Co2NbSn is paramagnetic above T-c = 116 K, it changes into a ferromagnetic state below T-c. Based upon the...

Quantitative line shape analysis of the Kondo resonance of cerium compounds (2002)

Ehm,D., Reinert,F., Schmidt,S., Nicolay,G., Hüfner,S., Kroha,J., ...

By use of high-resolution photoelectron spectroscopy we investigate the 4f spectral function of the heavy fermion compound CeRu2Si2 in the energy range close to the Fermi level. A normalization...

Cu-NQR study of CeCu2(Si0.98Ge0.02)2 under hydrostatic pressure (2002)

Kawasaki,Y., Ishida,K., Obinata,K., Mito,T., Zheng,G. Q., Kitaoka,Y., ...

We report a pressure effect on CeCu2(Si0.98Ge0.02)(2) where an anti ferromagnetic order below T-N similar to 0.75 K coexists with superconductivity below T-c similar to0.4 K. At pressures exceeding...

The magnetic phases of Ce(Cu1-xNix)2Ge2 (2002)

Klauss,H. H., Sullow,S., Walf,H., Mienert,D., Baabe,D., ...

The magnetic phase diagram of the system Ce(Cu1-xNix)(2)Ge-2 with 0less than or equal tox

NMR study of doped alpha '-NaV2O5 single crystals (2002)

Michalak,R., Mohammad,H., Dischner,M., Geibel,C.

Na-23 and V-51 NMR in the low temperature phase of sodium vanadate show the existence of three vanadium and 8 or 10 sodium sites. These are due to the charge ordering transition and the dimerization...

Non-Fermi liquid behaviour in cubic CeIn3-xSnx (2002)

Pedrazzini,P., Berisso,M. G., Caroca-Canales,N., Deppe,M., Geibel,C., Sereni,J. G.

The alloy between the antiferromagnetic (AF) CeIn3 and the mixed valent CeSn3 is particularly interesting since it is one of the few cases where a magnetic to non-magnetic transition is observed in a...

Effect of Ge-doping and pressure in the vicinity of the QCP of YbRh2Si2 (2002)

Trovarelli,O., Custers,J., Gegenwart,P., Geibel,C., Hinze,P., Mederle,S., ...

We present electrical resistivity (p) and AC magnetic susceptibility measurements on Ge-doped single crystals of the NFL compound YbRh2Si2. Upon producing the volume expansion (DeltaVsimilar or equal...

Evolution of magnetic order in the Kondo system Ce2Ir3Ge5 under pressure (2002)

Yuan,H. Q., Hossain,Z., Grosche,F. M., Sparn,G., Geibel,C., Steglich,F., ...

The evolution of antiferromagnetic order in the Kondo system Ce2Ir3Ge5 was investigated by measurements of the electrical resistivity under hydrostatic pressure. At low pressure (p < 1.0 GPa), T-N =...

Coexistence of antiferromagnetism and superconductivity in heavy-fermions systems (2002)

Kitaoka, Y., Kawasaki, Y., Mito, T., Kawasaki, S., Ishida, K., ...

We report the novel pressure(P)-temperature(T) phase diagrams of antiferromagnetism (AF) and superconductivity (SC) in CeRhIn$_5$, CeIn$_3$ and CeCu$_2$Si$_2$ revealed by the NQR measurement. In the...

Dielectric properties of the low dimensional vanadium oxides Ba2V3O9 and Sr2V3O9 (2002)

Bobnar,V., Lunkenheimer,P., Loidl,A., Kaul,E. E., Geibel,C.

The dielectric response of the low-dimensional vanadium oxides Ba2V3O9 and Sr2V3O9 has been investigated in the frequency range of 20 Hz-1 MHz. At low frequencies the dielectric response is governed...

Quasi-one-dimensional spin chains in CuSiO3: an EPR study (2002)

Sichelschmidt,J., Baenitz,M., Geibel,C., Steglich,F., Loidl,A., Otto,H. H.

Temperature-dependent electron paramagnetic resonance (EPR) studies were performed on CuSiO3. This recently discovered compound is isostructural with the spin-Peierls compound CuGeO3. The EPR signals...

Composition dependence of the magnetic properties of Ge-doped CeCu2Si2 (2002)

Berisso, M. G., Pedrazzini, P., Deppe, M., Trovarelli, O., Geibel, C., Sereni, J. G.

Due to the proximity of CeCu2Si2 to a quantum critical point, the ground state of this compound is extremely sensitive to sample preparation conditions. Small excess of one component can lead to...

Study of Ce(Rh1-xPdx)2Si2: pronounced differences between the CeRh2Si2 and CePd2Si2 ground states (2002)

Berisso, M. G., Pedrazzini, P., Sereni, J. G., Trovarelli, O., Geibel, C., Steglich, F.

We present electrical resistivity and specific heat measurements of alloys on the Rh rich side of the phase diagram of the Ce(Rh1-xPdx)(2)Si-2 system. We compare these results with those obtained at...

Dielectric properties of the low dimensional vanadium oxides Ba2V3O9 and Sr2V3O9 (2002)

Bobnar, V., Lunkenheimer, P., Loidl, A., Kaul, E. E., Geibel, C.

The dielectric response of the low-dimensional vanadium oxides Ba2V3O9 and Sr2V3O9 has been investigated in the frequency range of 20 Hz-1 MHz. At low frequencies the dielectric response is governed...

Quantitative line shape analysis of the Kondo resonance of cerium compounds (2002)

Ehm, D., Reinert, F., Schmidt, S., Nicolay, G., Hüfner, S., Kroha, J., ...

By use of high-resolution photoelectron spectroscopy we investigate the 4f spectral function of the heavy fermion compound CeRu2Si2 in the energy range close to the Fermi level. A normalization...

Magnetic-Field Induced Quantum Critical Point in YbRh2Si2 (2002)

Gegenwart, P., Custers, J., Geibel, C., Neumaier, K., Tayama, T., Tenya, K., ...

We report low-temperature calorimetric, magnetic, and resistivity measurements on the antiferromagnetic (AF) heavy- fermion metal YbRh2Si2 ( T-N=70 mK) as a function of magnetic field B. While for...

Antiferromagnetic transition in CePd2B2C and possible heavy- fermion behaviour in CePt2B2C (2002)

Hossain, Z., Geibel, C., Gupta, L. C., Nagarajan, R., Godart, C.

Our measurements of the magnetic susceptibility, resistivity and specific heat of CePd2B2C, a quaternary borocarbide, show clearly that Ce is in a stable trivalent state in this compound and orders...

Magnetic transition in the Kondo lattice system CeRhSn2 (2002)

Hossain, Z., Gupta, L. C., Geibel, C.

We present the results of our measurements of magnetization, heat capacity, resistivity and magnetoresistance on the Ce- based intermetallic compound CeRhSn2. The magnetic transition, as reported...

YbRh2Si2: Spin Fluctuations in the Vicinity of a Quantum Critical Point at Low Magnetic Field (2002)

Ishida, K., Okamoto, K., Kawasaki, Y., Kitaoka, Y., Trovarelli, O., Geibel, C., ...

We report a Si-29 NMR study on aligned single crystals of YbRh2Si2 which shows behavior characteristic of a quantum critical point (QCP: T-N-->0). The Knight shift K and the nuclear spin-lattice...

Spin-Triplet Superconductivity in UNi2Al3 Revealed by the 27Al Knightshift Measurement (2002)

Ishida, K., Ozaki, D., Kamatsuka, T., Tou, H., Kyogaku, M., Kitaoka, Y., ...

We report Al-27 Knight shift (K-27) measurement on a single- crystal UNi2Al3 that reveals a coexistence of superconductivity and a spin-density-wave (SDW) type of magnetic ordering (T- SDW=4.5 K )....

Cu-NQR study of CeCu2(Si0.98Ge0.02)2 under hydrostatic pressure (2002)

Kawasaki, Y., Ishida, K., Obinata, K., Mito, T., Zheng, G. Q., Kitaoka, Y., ...

We report a pressure effect on CeCu2(Si0.98Ge0.02)(2) where an anti ferromagnetic order below T-N similar to 0.75 K coexists with superconductivity below T-c similar to0.4 K. At pressures exceeding...

Exotic magnetism and superconductivity in Ge-substituted CeCu2Si2: A Cu NQR study (2002)

Kawasaki, Y., Ishida, K., Obinata, K., Tabuchi, K., Kashima, K., Kitaoka, Y., ...

We report Cu NQR results on Ge-doped heavy-fermion superconductors CeCu2(Si1-xGex)(2) (0< x≦0.2) and compare with previous results on Ce0.99Cu2.02Si2 (x=0). Once only 1% Ge is substituted for Si to...

Coexistence of antiferromagnetism and superconductivity in heavy-fermion systems (2002)

Kitaoka, Y., Kawasaki, Y., Mito, T., Kawasaki, S., Zheng, G. Q., Ishida, K., ...

We report the novel pressure (P)-temperature (T) phase diagrams of antiferromagnetism (AFM) and superconductivity (SC) in CeRhIn5, CeIn3, and CeCu2Si2 revealed by the nuclear quadrupole resonance...

The magnetic phases of Ce(Cu1-xNix)2Ge2 (2002)

Klauss, H. H., Sullow, S., Walf, H., Mienert, D., Baabe, D., ...

The magnetic phase diagram of the system Ce(Cu1-xNix)(2)Ge-2 with 0less than or equal tox

Evidence for the Coexistence of Superconductivity and the Magnetic A-Phase in CeCu2Si2 proved by Muon Knight Shift (2002)

Koda, A., Higemoto, W., Kadono, R., Kawasaki, Y., Ishida, K., Kitaoka, Y., ...

Muon spin rotation measurements under high transverse fields (HTF-ASR) have been performed on polycrystalline samples of Ce0.99Cu2.02Si2. The muon hyperfine coupling constant was determined to be...

An unconventional metallic state in YbRh2(Si1-xGex)2 - a high pressure study (2002)

Mederle, S., Borth, R., Geibel, C., Grosche, F. M., Sparn, G., Trovarelli, O., ...

We present a detailed pressure study of the electrical resistivity p(T) and the specific heat C(T) of the non-Fermi- liquid (NFL) compound YbRh2Si2, and of p(T) for a single crystal in which 5 at.%...

NMR study of doped alpha '-NaV2O5 single crystals (2002)

Michalak, R., Mohammad, H., Dischner, M., Geibel, C.

Na-23 and V-51 NMR in the low temperature phase of sodium vanadate show the existence of three vanadium and 8 or 10 sodium sites. These are due to the charge ordering transition and the dimerization...

Non-Fermi liquid behaviour in cubic CeIn3-xSnx (2002)

Pedrazzini, P., Berisso, M. G., Caroca-Canales, N., Deppe, M., Geibel, C., Sereni, J. G.

The alloy between the antiferromagnetic (AF) CeIn3 and the mixed valent CeSn3 is particularly interesting since it is one of the few cases where a magnetic to non-magnetic transition is observed in a...

Quasi-one-dimensional spin chains in CuSiO3: an EPR study (2002)

Sichelschmidt, J., Baenitz, M., Geibel, C., Steglich, F., Loidl, A., Otto, H. H.

Temperature-dependent electron paramagnetic resonance (EPR) studies were performed on CuSiO3. This recently discovered compound is isostructural with the spin-Peierls compound CuGeO3. The EPR signals...

Antiferromagnetic ordering in the Kondo lattice system Yb2Fe3Si5 (2002)

Singh, Y., Ramakrishnan, S., Hossain, Z., Geibel, C.

Compounds belonging to the R2Fe3Si5 series exhibit unusual superconducting and magnetic properties. Although a number of studies have been made on the first reentrant antiferromagnet superconductor...

Effect of Ge-doping and pressure in the vicinity of the QCP of YbRh2Si2 (2002)

Trovarelli, O., Custers, J., Gegenwart, P., Geibel, C., Hinze, P., Mederle, S., ...

We present electrical resistivity (p) and AC magnetic susceptibility measurements on Ge-doped single crystals of the NFL compound YbRh2Si2. Upon producing the volume expansion (DeltaVsimilar or equal...

Structure and magnetic order of the Heusler compound Co2NbSn (2002)

Wolter, A. U. B., Bosse, A., Baabe, D., Maksimov, I., Mienert, D., Klauss, H. H., ...

We present a detailed study of the structural and magnetic phase transitions of the Heusler compound Co2NbSn. This material undergoes a structural transition at T-S=235 K from the cubic Heusler Fm3m...

Magnetic history effects in the Heusler compound Co2NbSn (2002)

Wolter, A. U. B., Klauss, H. H., Litterst, F. J., Geibel, C., Süllow, S.

The magnetic properties of the Heusler compound Co2NbSn have been investigated. Whereas Co2NbSn is paramagnetic above T-c = 116 K, it changes into a ferromagnetic state below T-c. Based upon the...

Evolution of magnetic order in the Kondo system Ce2Ir3Ge5 under pressure (2002)

Yuan, H. Q., Hossain, Z., Grosche, F. M., Sparn, G., Geibel, C., Steglich, F., ...

The evolution of antiferromagnetic order in the Kondo system Ce2Ir3Ge5 was investigated by measurements of the electrical resistivity under hydrostatic pressure. At low pressure (p < 1.0 GPa), T-N =...

Study of the Ce(Rh$_{1-x}$Pd$_x$)$_2$Si$_2$ alloy: evidence for itinerant character of the magnetic order in CeRh$_2$Si$_2$ (2001)

Berisso, M. Gomez, Pedrazzini, P., Sereni, J. G., Trovarelli, O., Geibel, C., Steglich, F.

We present electrical resistivity and specific heat measurements of alloys on the Rh rich side of the phase diagram of the Ce(Rh$_{1-x}$Pd$_x$)$_2$Si$_2$ system and compare the results with those...

Ce-L3-XAS study of the temperature dependence of the 4f occupancy in the Kondo system Ce2Rh3Al9 (2001)

Grazioli, C., Hu, Z., Golden, M. S., Attenkofer, J. Fink K., Trovarelli, O., Geibel, C.

We have used temperature dependent x-ray absorption at the Ce-L3 edge to investigate the recently discovered Kondo compound Ce2Rh3Al9. The systematic changes of the spectral lineshape with decreasing...

Kondo effect in Ce(x)La(1-x)Cu(2.05)Si(2) intermetallics (2001)

Aviani, I., Miljak, M., Zlatic, V., Geibel, C., Steglich, F.

The magnetic susceptibility and susceptibility anisotropy of the quasi-binary alloy system Ce(x)La(1-x)Cu(2.05)Si(2) have been studied for low concentration of Ce ions. The single-ion desc ription is...

Temperature dependence of the Kondo resonance and its satellites in CeCu_2Si_2 (2001)

Reinert, F., Ehm, D., Schmidt, S., Nicolay, G., H"ufner, S., Kroha, J., ...

We present high-resolution photoemission spectroscopy studies on the Kondo resonance of the strongly-correlated Ce system CeCu$_2$Si$_2$. Exploiting the thermal broadening of the Fermi edge we...

Magnetic state in URu2Si2, UPd2Al3 and UNi2Al3 probed by point contacts (2001)

Naidyuk, Yu. G., Kvitnitskaya, O. E., Jansen, A. G. M., Geibel, C., Menovsky, A. A., Wyder, P.

The antiferromagnetic (AFM) state has been investigated in the three heavy-fermion compounds URu2Si2, UPd2Al3, and UNi2Al3 by measuring dV/dI(V) curves of point contacts at different temperatures...

Exotic Superconducting Phase in CeCu2Si2 Close to Antiferromagnetism : A Cu-NQR Study under Hydrostatic Pressure (2000)

Kawasaki, Y., Ishida, K., Mito, T., Thessieu, C., Kitaoka, Y., ...

We report Cu nuclear-quadrupole-resonance results under pressure on a homogeneous CeCu2Si2 (Tc = 0.65 K) that revealed critical magnetic fluctuations at the border to an antiferromagnetic phase. This...

Coexistence of Superconductivity and Antiferromagnetism in Heavy-Fermion Superconductor CeCu_{2}(Si_{1-x}Ge_{x})_{2} Probed by Cu-NQR --A Test Case for the SO(5) Theory-- (2000)

Kitaoka, Y., Ishida, K., Kawasaki, Y., Trovarelli, O., Geibel, C., Steglich, F.

We report on the basis of Cu-NQR measurements that superconductivity (SC) and antiferromagnetism (AF) coexist on a microscopic level in CeCu_{2}(Si_{1-x}Ge_{x})_{2}, once a tiny amount of 1%Ge (x =...

Optical properties and electronic structure of Ca-doped alpha'-NaV2O5 (2000)

Presura, C., Dischner, M., Geibel, C., Kremer, R. K.

The dielectric function of alpha'-Na(1-x)Ca(x)V2O5 (0 < x < 20%) was measured for the a and b axes in the photon energy range 0.8-4.5 eV at room temperature. By varying the Ca-concentration we...

CuSiO_3 : a quasi - one - dimensional S=1/2 antiferromagnetic chain system (2000)

Baenitz, M., Geibel, C., Dischner, M., Sparn, G., Steglich, F., Otto, H. H., ...

CuSiO_3, isotypic to the spin - Peierls compound CuGeO_3, was discovered recently as a metastable decomposition product of the silicate mineral dioptase, Cu_6Si_6O_{18}\cdot6H_2O. We investigated the...

Quasi-one-dimensional spin chains in CuSiO3: an EPR study (2000)

Sichelschmidt, J., Loidl, A., Baenitz, M., Otto, H. H., Geibel, C., Steglich, F.

Temperature dependent EPR studies were performed on a single crystal of CuSiO3.This recently discovered compound is isostructural with the spin-Peierls compound CuGeO3. The EPR signals show different...

Electron spin resonance study of Na_{1-x}Li_xV_2O_5 (1999)

Lohmann, M., Loidl, A., Morre, E., Dischner, M., Geibel, C.

We measured X-band electron-spin resonance of single crystalline sodium vanadate doped with lithium, Na_{1-x}Li_xV_2O_5 for 0 < x < 1.3% . The phase transition into a dimerized phase that is observed...

Spin gap behavior and charge ordering in \alpha^{\prime}-NaV_2O_5 probed by light scattering (1999)

Fischer, M., Lemmens, P., Els, G., Güntherodt, G., Sherman, E., Morre, E., ...

We present a detailed analysis of light scattering experiments performed on the quarter-filled spin ladder compound $\alpha^\prime$-NaV$_{2}$O$_{5}$ for the temperature range 5 K$\le$T$\le$300 K....

Elastic Constants and Charge Ordering in a'-NaV2O5 (1999)

Schwenk, H., Zherlitsyn, S., Luethi, B., Morre, E., Geibel, C.

We present the temperature dependence of shear and longitudinal elastic constants in a'-NaV2O5. For the longitudinal c22 and c33 modes we find anomalies at Tc in contrast to the Spin Peierls...

Magnetic bound states in the quarter-filled ladder system $\alpha'-NaV_{2}O_{5}$} (1998)

Lemmens, P., Fischer, M., Els, G., Güntherodt, G., Mishchenko, A. S., Weiden, M., ...

Raman scattering in the quarter-filled spin ladder system alpha'-NaV_2O_5 shows in the dimerized singlet ground state ($T \leq T_{SP}=35K$) an unexpected sequence of three magnetic bound states. Our...

Magnetic Bound States in Dimerized Quantum Spin Systems (1998)

Lemmens, P., Fischer, M., Grove, M., Els, G., Güntherodt, G., Weiden, M., ...

Magnetic bound states are a general phenomenon in low dimensional antiferromagnets with gapped singlet states. Using Raman scattering on three compounds as dedicated examples we show how exchange...

NaV_2O_5 as a quarter-filled ladder compound (1998)

Smolinski, H., Gros, C., Weber, W., Peuchert, U., Roth, G., Weiden, M., ...

A new X-ray diffraction study of the one-dimensional spin-Peierls compound \alpha-NaV_2O_5 reveals a centrosymmetric (Pmmn) crystal structure with one type of V site, contrary to the previously...

Magnetic Resonance in the Spin-Peierls compound $\alpha'-NaV_2O_5$ (1997)

Schmidt, S., Palme, W., Lüthi, B., Weiden, M., Hauptmann, R., Geibel, C.

We present results from magnetic resonance measurements for 75-350 GHz in $\alpha$'-NaV$_{2}$O$_{5}$. The temperature dependence of the integrated intensity indicates that we observe transitions in...

Interference of a first-order transition with the formation of a spin-Peierls state in alpha'-NaV2O5? (1997)

Koeppen, M., Pankert, D., Hauptmann, R., Lang, M., Weiden, M., Geibel, C., ...

We present results of high-resolution thermal-expansion and specific-heat measurements on single crystalline alpha'-NaV2O5. We find clear evidence for two almost degenerate phase transitions...

Normal-State Hall Effect and the Insulating Resistivity of High-T_c Cuprates at Low Temperatures (1997)

Ando, Yoichi, Boebinger, G. S., Passner, A., Wang, N. L., Geibel, C., Steglich, F., ...

The normal-state Hall coefficient R_H and the in-plane resistivity \rho_{ab} are measured in La-doped Bi_{2}Sr_{2}CuO_{y} (T_c \simeq 13 K) single crystals and La_{2-x}Sr_{x}CuO_{4} thin films by...

Effects of in-chain and off-chain substitutions on spin fluctuations in the spin-Peierls compound CuGeO_3 (1997)

Lemmens, P., Fischer, M., Güntherodt, G., Gros, C., Weiden, M., ...

The effect of in-chain and off-chain substitutions on 1D spin fluctuations in the spin-Peierls compound CuGeO_3 has been studied using Raman scattering in order to understand the interplay between...

Experimental evidence for a spin-Peierls-transition in $\alpha'-NaV_2O_5$ (1997)

Weiden, M., Hauptmann, R., Geibel, C., Steglich, F., Fischer, M., Lemmens, P., ...

We present the first measurements of magnetisation and Raman light scattering on $\alpha'-NaV_2O_5$ single crystals. Below 34 K, we observe a pronounced isotropic decrease of the susceptibility...