Y. J. Uemura

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...

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...

Superconductivity: Exotic Commonalities in Phase and Mode (2009)

Uemura, Y. J.

Recent muon and neutron experiments on the new FeAs-based superconductors revealed phase diagrams characterized by first-order evolution from antiferromagnetic to superconducting states, and an...

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

Energy-scale phenomenology and pairing via resonant spin-charge motion in FeAs, CuO, heavy-fermion and other exotic superconductors (2008)

Uemura, Y. J.

Muon spin relaxation ($\mu$SR) studies of the "1111" and "122" FeAs systems have detected static magnetism with variably sized ordered moments in their parent compounds. The phase diagrams of FeAs,...

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...

$\mu$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...

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...

Twin spin/charge roton mode and superfluid density: primary determining factors of $T_{c}$ in high-$T_{c}$ superconductors observed by neutron, ARPES, and $\mu$SR (2005)

Uemura, Y. J.

In the quest for primary factors which determine the transition temperature $T_{c}$ of high-$T_{c}$ cuprate superconductors (HTSC), we develop a phenomenological picture combining experimental...

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...

Dynamic properties of a diluted pyrochlore cooperative paramagnet (Tb_pY_{1-p})_2Ti_2O_7 (2004)

Keren, A., Gardner, J. S., Ehlers, G., Fukaya, A., Sagi, E., Uemura, Y. J.

Investigations of the spin dynamics of the geometrically frustrated pyrochlore (Tb_pY_{1-p})_2Ti_2O_7, using muon spin relaxation and neutron spin echo, as a function of magnetic coverage p, have...

Condensation, excitation, pairing, and superfluid density in high-$T_{c}$ superconductors: magnetic resonance mode as a roton analogue and a possible spin-mediated pairing (2004)

Uemura, Y. J.

To find out a primary determing factor of $T_{c}$ and a pairing mechanism in high-$T_{c}$ cuprates, we combine the muon spin relaxation results on $n_{s}/m^{*}$ (superconducting carrier density /...

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,...

Dynamic properties of a diluted pyrochlore cooperative paramagnet (TbpY1-p)2Ti2O7 (2004)

Keren, A, Gardner, J S, Ehlers, G, Fukaya, A, Segal, E, Uemura, Y J

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....

Superfluid density of high-Tc cuprate systems: implication on condensation mechanisms, heterogeneity and phase diagram (2002)

Uemura, Y. J.

Extensive muon spin relaxation measurements have been performed to determine the magnetic field penetration depth in high-Tc cuprate superconductors with simple hole doping, Zn-doping, overdoping,...

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...

Microscopic phase separation in the overdoped region of high-Tc cuprate superconductors (2001)

Uemura, Y. J.

We propose a phenomenological model for high-$T_{c}$ superconductors (HTSC) assuming: (1) a microscopic phase separation between superconducting and normal-metal areas in the overdoped region; and...

What can we learn from comparison between cuprates and He films ? : phase separation and fluctuating superfluidity (2000)

Uemura, Y. J.

In the underdoped, overdoped, Zn-doped or stripe-forming regions of high-$T_{c}$ cuprate superconductors (HTSC), the superfluid density $n_{s}/m^{*}$ at $T\to 0$ shows universal correlations with...

Magnetic dilution in the geometrically frustrated SrCr$_{9p}$Ga$_{12-9p}$O$_{19}$ and the role of local dynamics: a $\mu $SR study (2000)

Keren, A., Uemura, Y. J., Luke, G., Mendels, P., Mekata, M., Asano, T.

We investigate the spin dynamics of SrCr$_{9p}$Ga$_{12-9p}$O$_{19}$ for p below and above the percolation threshold p_c using muon spin relaxation. Our major findings are: (I) At T->0 the relaxation...

Magnetic dilution in the geometrically frustrated SrCr9pGa12-9pO19 and the role of local dynamics: A muon spin relaxation study (2000)

Keren, A, Uemura, Y J, Luke, G, Mendels, P, Mekata, M, Asano, T

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...

69,71Ga NMR in the kagomé lattice compound SrCr9-xGa3+xO19. (1998)

Keren, A., Mendels, P., Horvatić, M., Ferrer, F., Uemura, Y. J., Mekata, M., ...

Comment on "Muon spin relaxation studies of Zn-substitution effects in high-Tc cuprate superconductors" [and reply]. (1998)

Bernhard, C., Tallon, J., Bucci, C., DeRenzi, R., Guidi, G., Williams, G., ...

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...

Bose-Einstein to BCS Crossover Picture for High-T_c Cuprates (1997)

Uemura, Y. J.

Combining (1) the universal correlations between $T_{c}$ and $n_{s}/m^{*}$ (superconducting carrier density / effective mass) and (2) the pseudo-gap behavior in the underdoped region, we obtain a...

Cooper pairs as low-energy excitations in the normal state (1997)

Tchernyshyov, O., Uemura, Y. J.

We discuss the normal state of a fermionic system in an idealized PSEUDOGAP REGIME, $k_B T_c < k_B T

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...