Pair weakening in mixed rare-earth nickel borocarbides (R,R')Ni2B2C (2008)
Freudenberger, J., Fuchs, G., Wolf, M., Nenkov, K., Schultz, L.
In this study pseudoquaternary rare-earth nickel borocarbide superconductors RxR'1-xNi2B2C have been investigated predominantly in the diluted limit x
Low temperature transport and specific heat studies of $Nd_{1-x}Pb_xMnO_3$ single crystals (2008)
Ghosh, N, R¨oßler, UK, Nenkov, K, Hucho, C, Bhat, HL, M¨uller, KH
Electrical transport and specific heat properties of $Nd_{1-x}Pb_xMnO_3$ single crystals for $0.15\leq x \leq 0.5$ have been studied in the low temperature regime. The resistivity in the...
Fuchs, G., Kozlova, N., Behr, G., Koehler, A., Werner, J., ...
We report upper critical field B_c2(T) data for disordered (As deficient) LaO_0.9F_0.1FeAs_(1-delta) in a wide temperature and field range up to 47 T. Due to the large initial slope of dBc2/dT about...
Low Temperature Transport and Specific Heat Studies of Nd_{1-x}Pb_{x}MnO_{3} Single Crystals (2008)
Ghosh, N., Roessler, U. K., Nenkov, K., Hucho, C., Bhat, H. L., Mueller, K. H.
Electrical transport and specific heat properties of Nd_{1-x}Pb_{x}MnO_{3} single crystals for 0.15 < x 0.5 have been studied in low temperature regime. The resistivity in the ferromagnetic...
Strain-induced insulator state in La_0.7Sr_0.3CoO_3 (2007)
Rata, A. D., Herklotz, A., Nenkov, K., Schultz, L., Doerr, K.
We report on the observation of a strain-induced insulator state in ferromagnetic La_0.7Sr_0.3CoO_3 films. Tensile strain above 1% is found to enhance the resistivity by several orders of magnitude....
Naidyuk, Yu. G., Kvitnitskaya, O. E., Yanson, I. K., Fuchs, G., Nenkov, K., Waelte, A., ...
Point-contact (PC) spectroscopy measurements on antiferromagnetic (AF) (T_N=5.2K) HoNi2B2C single crystals in the normal and two different superconducting (SC) states (T_c=8.5K and $T_c^*=5.6K) are...
Point-contact spectroscopy of the antiferromagnetic superconductor HoNi2B2C (2006)
Naidyuk, Yu. G., Kvitnitskaya, O. E., Yanson, I. K., Fuchs, G., Nenkov, K., Walte, A., ...
The point-contact (PC) spectroscopy study of the electron-phonon(boson) interaction (EP(B)I) spectral function in HoNi2B2C reveals phonon maxima at 16 and 22meV and 34meV. For the first time the...
Nazarova, E. K., Nenkov, K., Fuchs, G.
The influence of Ca substitution on the superconducting properties of polycrystalline R1-xCaxBa2Cu3Oz (R = Eu, Gd, Er; x=0; 0.2; 0.25 and 0.3) samples has been studied by X-ray powder diffraction, ac...
Effect of Ta(5+) Substitution on the Ground State of CMR Manganites (2005)
Lakshmi, L. Seetha, Doerr, K., Nenkov, K., Handstein, A., Sridharan, V., Sastry, V. S., ...
In this paper, we discuss the most deleterious effect of charge state modification at the Mn site on the ground state of the CMR manganites.
Weak inter-band coupling in Mg$^{10}$B$_{2}$: a specific heat analysis (2005)
Wälte, A., Fuchs, G., Nenkov, K., Hinz, D., ...
The superconducting state of Mg$^{10}$B$_{2}$ is investigated by specific heat measurements in detail. The specific heat in the normal state is analyzed using a recently developed computer code. This...
The role of carbon for superconductivity in MgC$_{x}$Ni$_{3}$ from specific heat (2005)
Wälte, A., Fuchs, G., Nenkov, K., Schultz, L.
The influence of carbon deficiency on superconductivity of MgCNi$_{3}$ is investigated by specific heat measurements in the normal and superconducting state. In order to perform a detailed analysis...
Muntyanu, F. M., Gilewski, A., Nenkov, K., Warchulska, J., Zaleski, A. J.
Magnetization measurements prove that the magnetic properties of large-angle (theta > 30o) bismuth bicrystals with crystallite interface (CI) of twisting type essentially differ from well-known...
Strong Electron-Phonon Coupling and Sizeable depairing in MgCNi3 (2005)
Wälte,A., Fuchs,G., Handstein,A., Nenkov,K., Narozhnyi,V. N., ...
Strong Electron-Phonon Coupling and Sizeable depairing in MgCNi3 (2005)
Wälte, A., Fuchs, G., Handstein, A., Nenkov, K., Narozhnyi, V. N., ...
Evidence for strong electron-phonon coupling in MgCNi3 (2004)
Wälte,A., Fuchs,G., Handstein,A., Nenkov,K., Narozhnyi,V. N., ...
Ghosh, Nilotpal, Elizabeth, Suja, Bhat, HL, Rößler, UK, Nenkov, K, Rößler, S, ...
Single crystals of $La_{0.7–-y}Nd_yPb_{0.3}MnO_3$ with different y are grown by flux growth technique. The influence of change in average cationic radius $(\langle r_A\rangle)$ and cation size...
Naidyuk, Yu. G., Kvitnitskaya, O. E., Yanson, I. K., Fuchs, G., Nenkov, K., ...
An overview on recent efforts in point-contact (PC) spectroscopy of title superconductors is given. Distinct phonon features and crystalline-electric-field effects are observed in PC spectra of...
Structure, Tranport and Magnetism of La(0.67)Ca(0.33)Mn(1-x)Ta(x)O(3) (2004)
Lakshmi, L. Seetha, Doerr, K., Nenkov, K., Sridharan, V., Sastry, V. S.
For the first time,we report the effect of pentavalent subtitution at the Mn site of La(0.67)Ca(0.33)MnO(3). The ferromagnetic -metallic ground state modifies to a cluster-glass insulator beyond...
Non-magnetic superconducting R(Ni,Pt)2B2C compounds (R = Y, Lu) in the clean and dirty limit (2004)
Fuchs,G., Müller,K. H., Drechsler,S. L., Shulga,S., Nenkov,K., Freudenberger,J., ...
Rounding of a first-order magnetic phase transition in Ga doped La0.67Ca0.33MnO3 (2004)
Roessler, S., Roessler, U. K., Nenkov, K., Eckert, D., Yusuf, S. M., Dorr, K., ...
The effect of disorder on the critical properties of the ferromagnetic phase transition in colossal magnetoresistive manganite La0.67Ca0.33MnO3 has been studied by substituting Ga for Mn. It is found...
Skourski,Y., Fuchs,G., Kerschl,P., Kozlova,N., Eckert,D., Nenkov,K., ...
Evidence for strong electron-phonon coupling in MgCNi_3 (2004)
Waelte, A., Fuchs, G., Handstein, A., Nenkov, K., Narozhnyi, V. N., ...
The title compound is investigated by specific heat measurements in the normal and superconducting state supplemented by upper critical field transport, susceptibility and magnetization measurements....
Is U3Ni3Sn4 best described as near a quantum critical point? (2004)
Booth, C. H, Shlyk, L., Nenkov, K., Huber, J. G., De Long, L. E.
Although most known non-Fermi liquid (NFL) materials are structurally or chemically disordered, the role of this disorder remains unclear. In particular, very few systems have been discovered that...
Ghosh, Nilotpal, Elizabeth, Suja, Bhat, HL, Rößler, UK, Nenkov, K, Rößler, S, ...
Single crystals of $La_{0.7–-y}Nd_yPb_{0.3}MnO_3$ with different y are grown by flux growth technique. The influence of change in average cationic radius $(\langle r_A\rangle)$ and cation size...
Evidence for strong electron-phonon coupling in MgCNi3 (2004)
Wälte, A., Fuchs, G., Handstein, A., Nenkov, K., Narozhnyi, V. N., ...
Non-magnetic superconducting R(Ni,Pt)2B2C compounds (R = Y, Lu) in the clean and dirty limit (2004)
Fuchs, G., Müller, K. H., Drechsler, S. L., Shulga, S., Nenkov, K., Freudenberger, J., ...
Temperature dependence of trapped magnetic field in MgB2 bulk superconductor (2003)
Viznichenko, R. V., Kordyuk, A. A., Fuchs, G., Nenkov, K., Prikhna, T. A., ...
Based on DC magnetization measurements, the temperature dependencies of the trapped magnetic field have been calculated for two MgB2 samples prepared by two different techniques: the high-pressure...
Circular dichroism in angle-resolved photoemission spectra of under- and overdoped Pb-Bi2212 (2003)
Borisenko, S. V., Kordyuk, A. A., Koitzsch, A., Kim, T. K., Nenkov, K., Knupfer, M., ...
We use angle-resolved photoemission with circularly polarized excitation to demonstrate that in the 5x1 superstructure-free Pb-Bi2212 material there are no signatures of time-reversal symmetry...
Is U3Ni3Sn4 best described as near a quantum critical point? (2003)
Booth, C.H., Shlyk, L., Nenkov, K., Huber, J.G., De Long, L.E.
MgCNi3 : Complex behavior in a strongly coupled superconductor (2002)
Waelte, A., Rosner, H., Johannes, M. D., Fuchs, G., Handstein, A., ...
Polycrystalline samples of the recently discovered MgCNi3 superconductor were investigated by transport, ac susceptibility, dc magnetization and specific heat measurements in magnetic fields up to 16...
Comparative Study of Dense Bulk MgB$_2$ Materials Prepared by Different Methods (2002)
Narozhnyi, V. N., Fuchs, G., Handstein, A., Gümbel, A., Eckert, J., Nenkov, K., ...
We report on the results of a comparative investigation of highly dense bulk MgB$_2$ samples prepared by three methods: (i) hot deformation; (ii) high pressure sintering; and (iii) mechanical...
Specific heat and disorder in the mixed state of non-magnetic borocarbides (2002)
Lipp,D., Schneider,M., Gladun,A., Drechsler,S. L., Freudenberger,J., Fuchs,G., ...
The temperature and magnetic-field dependence of the specific heat c(p)(T, H) in the superconducting (sc) mixed state as well as the upper critical field H-c2(T) have been measured for...
Influence of disorder on superconductivity in non-magnetic rare-earth nickel borocarbides (2002)
Fuchs,G., Müller,K. H., Freudenberger,J., Nenkov,K., Drechsler,S. L., Shulga,S. V., ...
Specific heat and disorder in the mixed state of non-magnetic borocarbides (2002)
Lipp, D., Schneider, M., Gladun, A., Drechsler, S. L., Freudenberger, J., Fuchs, G., ...
The temperature and magnetic-field dependence of the specific heat c(p)(T, H) in the superconducting (sc) mixed state as well as the upper critical field H-c2(T) have been measured for...
Influence of disorder on superconductivity in non-magnetic rare-earth nickel borocarbides (2002)
Fuchs, G., Müller, K. H., Freudenberger, J., Nenkov, K., Drechsler, S. L., Shulga, S. V., ...
Improved superconducting properties in nanocrystalline bulk MgB_2 (2001)
Gümbel, A., Eckert, J., Fuchs, G., Nenkov, K., Schultz, L.
Highly dense nanocrystalline MgB_2 bulk superconductors with distinctly improved pinning were prepared by mechanical alloying of Mg and B powders and hot compaction at ambient temperatures. The...
Origin of the peak-dip-hump structure in the photoemission spectra of Bi2212 (2001)
Kordyuk, A. A., Borisenko, S. V., Kim, T. K., Nenkov, K., Knupfer, M., Golden, M. S., ...
The famous peak-dip-hump lineshape of the (\pi,0) photoemission spectrum of the bilayer Bi HTSC in the superconducting state is shown to be a superposition of spectral features originating from...
Electronic structure and weak electron-phonon coupling in TaB$_2$ (2001)
Rosner, H., Pickett, W. E., Handstein, A., Behr, G., Fuchs, G., ...
We present electronic structure calculations together with resistivity, susceptibility, and specific heat measurements for TaB$_2$ to search for the recently contradictorily reported...
Specific heat and disorder in the mixed state of non-magnetic borocarbides (2001)
Lipp, D., Schneider, M., Gladun, A., Freudenberger, J., Fuchs, G., ...
The temperature and magnetic field dependence of the specific heat cp(T,H) in the superconducting mixed state as well as the upper critical field Hc2(T) have been measured for polycrystalline...
Upper critical field and irreversibility line in superconducting MgB_2 (2001)
Fuchs, G., Handstein, A., Nenkov, K., Narozhnyi, V. N., Eckert, D., ...
The upper critical field Hc2(T) of sintered pellets of the recently discovered MgB_2 superconductor was investigated by transport, ac susceptibility and dc magnetization measurements in magnetic...
Fully dense MgB_2 superconductor textured by hot deformation (2001)
Handstein, A., Hinz, D., Fuchs, G., Nenkov, K., Gutfleisch, O., ...
Bulk textured MgB_2 material of nearly full density showing a weak c-axis alignment of the hexagonal MgB_2 grains parallel to the pressure direction was obtained by hot deformation of a...
The upper critical field in superconducting MgB_2 (2001)
Fuchs, G., Handstein, A., Nenkov, K., Narozhnyi, V. N., Eckert, D.
The upper critical field Hc2(T) of sintered pellets of the recently discovered MgB_2 superconductor was investigated in magnetic fields up to 16 T. The upper critical field of the major fraction of...
Borisenko, S. V., Kordyuk, A. A., Legner, S., Duerr, C., Knupfer, M., Golden, M. S., ...
The strong dependence of the momentum distribution of the photoelectrons on experimental conditions raises the question as to whether angle-resolved photoemission spectroscopy (ARPES) is able to...
INFLUENCE OF DISORDER ON SUPERCONDUCTIVITY IN RARE-EARTH NICKEL BOROCARBIDES (2001)
Fuchs,G., Freudenberger,J., Nenkov,K., Rosner,H., ...
SPECIFIC HEAT OF YxLu1-xNi2B2C IN THE MIXED STATE (2001)
Lipp,D., Schneider,M., Gladun,A., Freudenberger,J., Fuchs,G., ...
SPECIFIC HEAT OF YxLu1-xNi2B2C IN THE MIXED STATE (2001)
Lipp, D., Schneider, M., Gladun, A., Freudenberger, J., Fuchs, G., ...
Current-induced conductance switching in epitaxial La0.7Sr0.3MnO3/SrTiO3 multilayers (2000)
Doerr, K., Walter, T., Sahana, M., Eckert, D., Nenkov, K., ...
We report on the non-linear in-plane electrical transport in coherently grown [La0.7Sr0.3MnO3/SrTiO3] multilayers with ultrathin (< 3 nm) single layers. Current-induced switching of the conductance,...
Specific heat of (Y,Lu)Ni2B2C in the mixed state (2000)
Lipp, D., Schneider, M., Gladun, A., Freudenberger, J., Fuchs, G., ...
The temperature and magnetic field dependences of the electronic specific heat in the superconducting mixed state as well as the upper critical field have been measured on a (Y,Lu)Ni2B2C series to...
Proximity Effect in Bulk LaBa_2Cu_3O_{7-y} Samples with Ag Additions (2000)
Nazarova, E., Zahariev, A., Angelow, A., Nenkov, K.
Bulk LaBa_2Cu_3O_(7-y) samples with different Ag additions were investigated. It was shown that Ag does not enter the crystallographic structure of the superconductor and segregates on the grain...
Magnetism of $Ti^{4+}$ diluted manganites $La_{1-x} Pb_x Mn_{1-y}Ti_yO_3$ $(y\leq x)$ (2000)
Sahana, M, Dorr, K, Doerr, M, Eckert, D, Muller, KH, Nenkov, K, ...
The effect of nonmagnetic $Ti^{4+}$ substitution for $Mn^{4+}$ on magnetic ordering of $La_{1-x}Pb_x Mn_{1-y} Ti_y O_3$ $(x=0.15, 0.26, and 0.4; 0\leq y \leq x)$ has been studied. The ferromagnetic...
Magnetism of $Ti^{4+}$ diluted manganites $La_{1-x} Pb_x Mn_{1-y}Ti_yO_3$ $(y\leq x)$ (2000)
Sahana, M, Dorr, K, Doerr, M, Eckert, D, Muller, KH, Nenkov, K, ...
The effect of nonmagnetic $Ti^{4+}$ substitution for $Mn^{4+}$ on magnetic ordering of $La_{1-x}Pb_x Mn_{1-y} Ti_y O_3$ $(x=0.15, 0.26, and 0.4; 0\leq y \leq x)$ has been studied. The ferromagnetic...
Magnetic properties of Gd_{1-x}Pr_xBa_2Cu_3O_{7-y} single crystals (1999)
Narozhnyi, V. N., Eckert, D., Fuchs, G., Nenkov, K., Uvarova, T. G.
Magnetic properties were studied for the high quality Al-free orthorhombic Gd_{1-x}Pr_xBa_2Cu_3O_{7-y} single crystals (0