G. M. Luke

Study of the ground state properties of $LiHo_xY_{1-x}F_4$ using $\mu$SR (2009)

Rodriguez, J., Aczel, A. A., Carlo, J. P., Dunsiger, S. R., MacDougall, G. J., Russo, P. L., ...

$LiHo_xY_{1-x}F_4$ is an insulating system where the magnetic Ho$^{3+}$ ions have an Ising character, and interact mainly through magnetic dipolar fields. We used the muon spin relaxation technique...

NMR Studies of Heavily Overdoped Ba1-xKxFe2As2 Superconductors (2009)

Zhang, S. W., Ma, L., Hou, Y. D., Zhang, J. S., Xia, T. L., Chen, G. F., ...

We performed NMR studies on two overdoped high-quality Ba$_{0.3}$K$_{0.7}$Fe$_2$As$_2$ and KFe$_2$As$_2$ single crystals. In the normal states of the two samples, we found an anisotropy of the...

Field-induced Bose-Einstein Condensation of triplons up to 8 K in Sr3Cr2O8 (2009)

Aczel, A. A., Kohama, Y., Marcenat, C., Weickert, F., Ayala-Valenzuela, O. E., Jaime, M., ...

Single crystals of the spin dimer system Sr3Cr2O8 have been grown for the first time. Magnetization, heat capacity, and magnetocaloric effect data up to 65 T reveal magnetic order between applied...

Muon Spin Rotation Measurement of the Magnetic Field Penetration Depth in Ba(Fe0.93 Co0.07)2 As2 : Evidence for Multiple Superconducting Gaps (2009)

Williams, T. J., Aczel, A. A., Baggio-Saitovitch, E., Budko, S. L., Canfield, P. C., Carlo, J. P., ...

We have performed transverse field muon spin rotation measurements of single crystals of Ba(Fe$_{0.93}$Co$_{0.07})_2$As$_2$ with the applied magnetic field along the $\hat{c}$ direction. Fourier...

Bose-Einstein Condensation of Triplons in Ba3Cr2O8 (2009)

Aczel, A. A., Kohama, Y., Jaime, M., Balicas, L., Ninios, K., Chan, H. B., ...

By performing heat capacity, magnetocaloric effect, torque magnetometry and force magnetometry measurements up to 33 T, we have mapped out the T-H phase diagram of the S = 1/2 spin dimer compound...

Impact of Fe doping on the spin structure of MnSi. (2009)

Lamago, D., Reznik, D., Uemura, Y.J., Goko, T., Wolf, Th., Grigoriev, S.V., ...

Internat.Conf.on Magnetism (ICM 2009), Karlsruhe, July 26-31, 2009

The Absence of Superconductivity in Single Phase CaFe2As2 under Hydrostatic Pressure (2008)

Yu, W., Aczel, A. A., Williams, T. J., Bud'ko, S. L., Ni, N., Canfield, P. C., ...

Recent high-pressure studies found that superconductivity can be achieved under very low pressure in the parent iron arsenide compound CaFe2As2, although details of the sharpness and temperature of...

Weak quasistatic magnetism in the frustrated Kondo lattice Pr_2Ir_2O_7 (2008)

MacLaughlin, D. E., Ohta, Y., Machida, Y., Nakatsuji, S., Luke, G. M., Ishida, K., ...

Muon spin relaxation experiments have been performed in the pyrochlore iridate Pr_2Ir_2O_7 for temperatures in the range 0.025-250 K. Kubo-Toyabe relaxation functions are observed up to > 200 K,...

Superconductivity coexisting with phase-separated static magnetic order in (Ba,K)Fe$_{2}$As$_{2}$, (Sr,Na)Fe$_{2}$As$_{2}$ and CaFe$_{2}$As$_{2}$ (2008)

Goko, T., Aczel, A. A., Baggio-Saitovitch, E., Bud'ko, S. L., Canfield, P. C., Carlo, J. P., ...

The recent discovery and subsequent developments of FeAs-based superconductors have presented novel challenges and opportunities in the quest for superconducting mechanisms in correlated-electron...

Muon spin relaxation studies of magnetic order and superfluid density in antiferromagnetic NdOFeAs, BaFe2As2 and superconducting (Ba,K)Fe2As2 (2008)

Aczel, A. A., Baggio-Saitovitch, E., Budko, S. L., Canfield, P. C., Carlo, J. P., Chen, G. F., ...

Zero-field (ZF) muon spin relaxation ($\mu$SR) measurements have revealed static commensurate magnetic order of Fe moments in NdOFeAs below $T_{N} \sim 135$ K, with the ordered moment size nearly...

Itinerant spin excitations near the hidden order transition in URu2Si2 (2008)

Janik, J. A., Zhou, H. D., Balicas, L., MacDougall, G. J., Luke, G. M., ...

By means of neutron scattering we show that the high-temperature precursor to the hidden order state of the heavy fermion superconductor URu$_{2}$Si$_{2}$ exhibits heavily damped incommensurate...

$\mu$SR studies of the frustrated quasi-2d square-lattice spin system Cu(Cl,Br)La(Nb,Ta)$_{2}$O$_{7}$: evolution from spin-gap to antiferromagnetic state (2008)

Uemura, Y. J., Aczel, A. A., Ajiro, Y., Carlo, J. P., Goko, T., Goldfeld, D. A., ...

We report muon spin relaxation ($\mu$SR) and magnetic susceptibility measurements on Cu(Cl,Br)La(Nb,Ta)$_{2}$O$_{7}$, which demonstrate: (a) the absence of static magnetism in (CuCl)LaNb$_{2}$O$_{7}$...

Signatures of Heterogeneous Magnetism in Overdoped La2-xSrxCuO4 from Muon Spin Rotation (2008)

MacDougall, G. J., Aczel, A. A., Birgeneau, R. J., Ito, T., Kim, H., ...

We present TF-\mu SR data on heavily overdoped La2-xSrxCuO4, which show a large, field-induced broadening of the local magnetic field distribution up to high temperatures well above T_{c}. The doping...

MuSR studies of RE(O,F)FeAs (RE = La, Nd, Ce) and LaOFeP systems: possible incommensurate/stripe magnetism and superfluid density (2008)

Carlo, J. P., Uemura, Y. J., Goko, T., MacDougall, G. J., Rodriguez, J. A., Yu, W., ...

Muon spin relaxation (MuSR) measurements in iron oxy-pnictide systems have revealed: (1) commensurate long-range order in undoped LaOFeAs; (2) Bessel function line shape in La(O0.97F0.03)FeAs which...

Absence of time reversal symmetry breaking in La_{2-x}Sr_{x}CuO_{4} (2008)

MacDougall, G. J., Aczel, A. A., Carlo, J. P., Ito, T., Rodriguez, J., Russo, P. L., ...

We have performed zero-field muon spin rotation measurements on single crystals of La_{2-x}Sr_{x}CuO_{4} to search for spontaneous currents in the pseudo-gap state. By comparing measurements on...

Gapped itinerant spin excitations account for missing entropy in the hidden order state of URu$_2$Si$_2$ (2007)

Wiebe, C. R., Janik, J. A., Macdougall, G. J., Luke, G. M., Garrett, J. D., Zhou, H. D., ...

One of the primary goals of modern condensed matter physics is to elucidate the nature of the ground state in various electronic systems. Many correlated electron materials, such as high temperature...

Impurity-induced singlet breaking in SrCu2(BO3)2 (2007)

Aczel, A. A., MacDougall, G. J., Rodriguez, J. A., Luke, G. M., Russo, P. L., Savici, A. T., ...

We have performed $\mu$SR studies on single crystals of SrCu$_2$(BO$_3$)$_2$, a quasi-two-dimensional spin system with a spin singlet ground state. We observe two different muon sites which we...

Phase separation and suppression of critical dynamics at quantum transitions of itinerant magnets: MnSi and (Sr$_{1-x}$Ca$_{x}$)RuO$_{3}$ (2006)

Uemura, Y. J., Goko, T., Gat-Malureanu, I. M., Carlo, J. P., Russo, P. L., Savici, A. T., ...

Quantum phase transitions (QPTs) have been studied extensively in correlated electron systems. Characterization of magnetism at QPTs has, however, been limited by the volume-integrated feature of...

The Anderson-Mott transition induced by hole-doping in Nd1-xTiO3 (2006)

Sefat, A. S., Greedan, J. E., Luke, G. M., Niewczas, M., Garrett, J. D., Dabkowska, H., ...

The insulator/metal transition induced by hole-doping due to neodymium vacancies of the Mott- Hubbard antiferromagnetic insulator, Nd1-xTiO3, is studied over the composition range 0.010(6) < x <...

2D Kagome Ordering in the 3D Frustrated Spinel Li2Mn2O4 (2005)

Wiebe, C. R., Russo, P. L., Savici, A. T., Uemura, Y. J., MacDougall, G. J., Luke, G. M., ...

muSR experiments on the geometrically frustrated spinel oxide, Li2Mn2O4, show the development of spin correlations over a range of length scales with decreasing temperature. Increased relaxation...

Muon Spin Relaxation Studies of Magnetic-Field-Induced Effects in High-$T_{c}$ Superconductors (2004)

Savici, A. T., Fukaya, A., Gat-Malureanu, I. M., Ito, T., Russo, P. L., Uemura, Y. J., ...

Muon spin relaxation ($\mu$SR) measurements in high transverse magnetic fields ($\parallel \hat c$) revealed strong field-induced quasi-static magnetism in the underdoped and Eu doped...

Magnetic ordering in the spin-ice candidate Ho{2}Ru{2}O{7} (2004)

Wieble, C.R., Gardner, J.S., Luke, G.M., Wills, A.S., Gaulin, D.B., ...

Neutron scattering measurements on the spin-ice candidate material Ho2Ru2O7 have revealed two magnetic transitions at T∼95 and ∼1.4   K to long-range ordered states involving the Ru and Ho...

Magnetic Ordering in the Spin-Ice Candidate Ho$_2$Ru$_2$O$_7$ (2004)

Wiebe, C. R., Gardner, J. S., Luke, G. M., Wills, A. S., Gaulin, B. D., ...

Neutron scattering measurements on the spin-ice candidate material Ho$_2$Ru$_2$O$_7$ have revealed two magnetic transitions at T $\sim$ 95 K and T $\sim$ 1.4 K to long-range ordered states involving...

Site-Dilution in quasi one-dimensional antiferromagnet Sr2(Cu1-xPdx)O3: reduction of Neel Temperature and spatial distribution of ordered moment sizes (2004)

Kojima, K. M., Yamanobe, J., Eisaki, H., Uchida, S., Fudamoto, Y., Gat, I. M., ...

We investigate the Neel temperature of Sr2CuO3 as a function of the site dilution at the Cu (S=1/2) sites with Pd (S=0), utilizing the muon spin relaxation (muSR) technique. The Neel temperature,...

Unconventional superconductivity in Na$_{0.35}$CoO$_{2}\cdot$1.3D$_{2}$O and proximity to a magnetically ordered phase (2004)

Uemura, Y. J., Russo, P. L., Savici, A. T., Wiebe, C. R., MacDougall, G. J., Luke, G. M., ...

Muon spin relaxation ($\mu$SR) measurements on the new layered cobalt oxide superconductor Na$_{0.35}$CoO$_{2}\cdot$1.3H$_{2}$O and its parent, non-superconducting compounds, have revealed...

Expansion of Vortex Cores by Strong Electronic Correlation in La$_{2-x}$Sr$_x$CuO$_4$ at Low Magnetic Induction (2004)

Kadono, R., Higemoto, W., Koda, A., Larkin, M. I., Luke, G. M., Savici, A. T., ...

The vortex core radius \rv, defined as the peak position of the supercurrent around the vortex, has been determined by muon spin rotation measurements in the mixed state of \lscox for $x=0.13$, 0.15,...

Two dimensional nature of superconductivity in intercalated layered systems Li$_{x}$HfNCl and Li$_{x}$ZrNCl: muon spin relaxation and magnetization measurements (2003)

Ito, T., Fudamoto, Y., Fukaya, A., Gat-Malureanu, I. M., Larkin, M. I., Russo, P. L., ...

We report muon spin relaxation ($\mu$SR) and magnetization measurements, together with synthesis and characterization, of the Li-intercalated layered superconductors Li$_{x}$HfNCl and Li$_{x}$ZrNCl...

Muon Spin Relaxation and Susceptibility Studies of Pure and Doped Spin 1/2 Kagom\'{e}-like system (Cu$_x$Zn$_{1-x}$)$_{3}$V$_{2}$O$_7$(OH)$_{2}$ 2H$_2$O (2003)

Fukaya, A., Fudamoto, Y., Gat, I. M., Ito, T., Larkin, M. I., Savici, A. T., ...

Muon spin relaxation ($\mu$SR) and magnetic susceptibility measurements have been performed on the pure and diluted spin 1/2 kagom\'{e} system (Cu$_x$Zn$_{1-x}$)$_{3}$V$_{2}$O$_7$(OH)$_{2}$ 2H$_2$O....

Hidden orbital currents and spin gap in the heavy fermion superconductor URu$_2$Si$_2$ (2003)

Wiebe, C. R., Luke, G. M., Yamani, Z., Menovsky, A. A., Buyers, W. J. L.

We have performed neutron scattering experiments on the heavy fermion superconductor URu$_2$Si$_2$ to search for the orbital currents predicted to exist in the ordered phase below {\Tn} = 17.5 K....

Superconductivity and Field-Induced Magnetism in Pr$_{2-x}$Ce$_x$CuO$_4$ Single Crystals (2003)

Sonier, J. E., Poon, K. F., Luke, G. M., Kyriakou, P., Miller, R. I., Liang, Ruixing, ...

We report muon-spin rotation/relaxation (muSR) measurements on single crystals of the electron-doped high-T_c superconductor Pr$_{2-x}$Ce$_x$CuO$_4$. In zero external magnetic field,...

Muon spin relaxation studies of incommensurate magnetism and superconductivity in stage-4 La$_{2}$CuO$_{4.11}$ and La$_{1.88}$Sr$_{0.12}$CuO$_{4}$ (2002)

Savici, A. T., Fudamoto, Y., Gat, I. M., Ito, T., Larkin, M. I., Uemura, Y. J., ...

This paper reports muon spin relaxation (MuSR) measurements of two single crystals of the title high-Tc cuprate systems where static incommensurate magnetism and superconductivity coexist. By...

muSR studies of the Kagome antiferromagnet (H3O)Fe3(OH)6(SO4)2 (2000)

Harrison, A, Kojima, K M, Wills, A S, Fudamato, Y, Larkin, M I, Luke, G M, ...

Muon Spin Relaxation and Nonmagnetic Kondo State in PrInAg_2 (1998)

MacLaughlin, D. E., Heffner, R. H., Nieuwenhuys, G. J., Canfield, P. C., Amato, A., Baines, C., ...

Muon spin relaxation experiments have been carried out in the Kondo compound PrInAg_2. The zero-field muon relaxation rate is found to be independent of temperature between 0.1 and 10 K, which rules...

Time-Reversal Symmetry Breaking Superconductivity in Sr2RuO4 (1998)

Luke, G. M., Fudamoto, Y., Kojima, K. M., Larkin, M. I., Merrin, J., Nachumi, B., ...

We report muon spin relaxation measurements on the superconductor Sr2RuO4 that reveal the spontaneous appearance of an internal magnetic field below the transition temperature: the appearance of such...

Susceptibility inhomogeneity and non-Fermi liquid behavior in nominally ordered UCu_4Pd (1998)

MacLaughlin, D. E., Heffner, R. H., Nieuwenhuys, G. J., Luke, G. M., Fudamoto, Y., Uemura, Y. J., ...

Muon spin rotation experiments on a stoichiometric sample of the non-Fermi liquid (NFL) heavy-fermion compound UCu_4Pd, in which recent neutron Bragg scattering measurements are consistent with an...

Muon Spin Relaxation Study of Reentrant Spin Glasses: Amorphous-Fe_{1-x}Mn_x (1997)

Gingras, M. J. P., Larkin, M., Mirebeau, I., Wu, W. D., Kojima, K., Luke, G. M., ...

We have performed an extensive muon spin relaxation study of the well known (Fe$_{1-x}$Mn$_{x}$)$_{75}$P$_{16}$B$_6$Al$_3$ reentrant spin glass. We find a strong increase of the dynamic as well as...

Observation of Spin Freezing in CaV4O9 and CaV2O5 by uSR (1997)

Luke, G. M., Fudamoto, Y., Kojima, K. M., Larkin, M., Merrin, J., Nachumi, B., ...

We have performed muon spin relaxation and susceptibility measurements of CaV_4O_9 and CaV_2O_5, systems in which spin gap-like behavior has been found. We observe spin freezing in the two compounds...

Muon-Spin Rotation Measurements of the Magnetic Field Dependence of the Vortex-Core Radius and Magnetic Penetration Depth in NbSe2 (1997)

Sonier, J. E., Kiefl, R. F., Brewer, J. H., Chakhalian, J., Dunsiger, S. R., MacFarlane, W. A., ...

Muon-spin rotation spectroscopy has been used to measure the internal magnetic field distribution in NbSe2 for Hc1

Reduction of ordered moment and Neel temperature of quasi one-dimensional antiferromagnets Sr2CuO3 and Ca2CuO3 (1997)

Kojima, K. M., Fudamoto, Y., Larkin, M., Luke, G. M., Merrin, J., Nachumi, B., ...

We report elastic neutron diffraction and muon spin relaxation (muSR) measurements of the quasi one-dimensional antiferromagnets Sr2CuO3 and Ca2CuO3, which have extraordinarily reduced TN/J ratios....

Reduction of ordered moment and Neel temperature of quasi one-dimensional antiferromagnets Sr (1997)

And Ca, Ca Cuo, K. M. Kojima, Y. Fudamoto, M. Larkin, ...

We report elastic neutron di#raction and muon spin relaxation (µSR) measurements of the quasi one-dimensional antiferromagnets Sr 2 CuO 3 and Ca 2 CuO 3 , which have extraordinarily reduced TN /J...

Muon Spin Relaxation Investigation of the Spin Dynamics of Geometrically Frustrated Antiferromagnets Y2Mo2O7 and Tb2Mo2O7 Static Critical Behavior of the Spin-Freezing (1996)

Dunsiger, S. R., Kiefl, R. F., Chow, K. H., Gaulin, B. D., Gingras, M. J. P., Greedan, J. E., ...

The spin dynamics of geometrically frustrated pyrochlore antiferromagnets Y2Mo2O7 and Tb2Mo2O7 have been investigated using muon spin relaxation. A dramatic slowing down of the moment fluctuations...

Intramolecular motion in organic radicals studied by muon spin rotation and level crossing resonance (1989)

Percival, P W, Brodovitch, J-C, Leung, S-K, Yu, D, Kiefl, R F, Garner, D M, ...

IOP Short Meetings Series No 22 (IOP Bristol, 1989) 99 (1989)

Intramolecular motion in organic free radicals (ethyl, t-butyl and cyclohexadienyl) studied by muon spin rotation and level-crossing spectroscopy (1988)

Percival, P W, Brodovitch, J-C, Leung, S-K, Yu, D, Kiefl, R F, Luke, G M, ...

in Organic Free Radicals, eds H Rischer, H Heimgartner, Springer-Verlag (1988)

Intramolecular motion in the tertiary-butyl radical as studied by muon spin rotation and level-crossing resonance (1988)

Percival, P W, Brodovitch, J-C, Leung, S-K, Yu, D, Kiefl, R F, Luke, G M, ...

Muon level-crossing spectroscopy of organic free radicals (1987)

Percival, P W, Kiefl, R F, Kreitzman, S R, Garner, D M, Cox, S F J, Luke, G M, ...