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Shu, L.*; Higemoto, Wataru; Aoki, Yuji*; Hillier, A. D.*; Oishi, Kazuki*; Ishida, Kenji*; Kadono, Ryosuke*; Koda, Akihiro*; Bernal, O. O.*; MacLaughlin, D. E.*; et al.
Physical Review B, 83(10), p.100504_1 - 100504_4, 2011/03
Times Cited Count:34 Percentile:76.91(Materials Science, Multidisciplinary)Zero-field muon spin relaxation experiments have been carried out in the Pr(OsRu)Sb and PrLaOsSb alloy systems to investigate broken time-reversal symmetry (TRS) in the superconducting state, signaled by the onset of a spontaneous static local magnetic field B. In both alloy series B initially decreases linearly with solute concentration. Ru doping is considerably more efficient than La doping, with a 50% faster initial decrease. The data suggest that broken TRS is suppressed for Ru concentration 0.6 but persists for essentially all La concentrations. Our data support a crystal-field excitonic cooper pairing mechanism for TRS-breaking superconductivity.
Sato, Hideyuki*; Aoki, Yuji*; Kikuchi, Daisuke*; Sugawara, Hitoshi*; Higemoto, Wataru; Oishi, Kazuki; Ito, Takashi; Heffner, R. H.; Saha, S. R.*; Koda, Akihiro*; et al.
Physica B; Condensed Matter, 404(5-7), p.749 - 753, 2009/04
Times Cited Count:5 Percentile:24.86(Physics, Condensed Matter)Wide varieties of strongly correlated electron phenomena are performed on the stage of a filled skutterudite structure. Especially when one of the players contains a plural number of 4f electrons, the orbital degrees of freedom play a major role as a new type of nonmagnetic and/or weak-magnetic phenomena. Several examples found in Pr- and Sm-based filled skutterudites are introduced in relation to muon spin relaxation experiments.
Oishi, Kazuki; Heffner, R. H.; Ito, Takashi; Higemoto, Wataru; Morris, G. D.*; Bauer, E. D.*; Graf, M. J.*; Zhu, J.-X.*; Morales, L. A.*; Sarrao, J. L.*; et al.
Physica B; Condensed Matter, 403(5-9), p.1013 - 1014, 2008/04
Times Cited Count:0 Percentile:0.00(Physics, Condensed Matter)PuCoGa has attracted much interest because it is the first Pu-based superconductor, having an order of magnitude higher transition temperature K than the isostructural heavy fermion superconductor CeCoIn (K). The mechanism of the superconductivity in PuCoGa is still under investigation, though recent experiments and theory suggest a magnetic origin. A unique aspect of this compound is the self-irradiation damage because Pu (Pu, = 24,000 years) creates lattice defects which scatter electrons and, hence, break superconducting pairs. In order to elucidate the magnitude and temperature dependence of the magnetic penetration depth , we have performed SR measurements in the same PuCoGa single crystals after 25 and 400 days of aging. We found that decreased from 18.5K to 15K for the aged sample, yet a quasi-linear temperature dependence was found for the low-temperature in both the fresh and aged sample, consistent with -wave pairing symmetry. The magnitude of the muon spin relaxation rate in the aged sample, , where and are the superfluid density and the effective mass, respectively, is reduced by about 70% compared to fresh sample. This indicates that the scattering from self-irradiation induced defects is not in the limit of the conventional Abrikosov-Gor'kov pair-breaking theory, but rather in the limit of short coherence length (about 2nm in PuCoGa) superconductivity.
Oishi, Kazuki; Heffner, R. H.; Ito, Takashi; Higemoto, Wataru; Morris, G. D.*; Hur, N.*; Bauer, E. D.*; Sarrao, J. L.*; Thompson, J. D.*; MacLaughlin, D. E.*; et al.
Journal of Physics and Chemistry of Solids, 68(11), p.2068 - 2071, 2007/11
Times Cited Count:2 Percentile:12.81(Chemistry, Multidisciplinary)no abstracts in English
Heffner, R. H.; Oishi, Kazuki; Fluss, M. J.*; Morris, G. D.*; MacLaughlin, D. E.*; Shu, L.*; Chung, B. W.*; McCall, S. K.*; Bauer, E. D.*; Sarrao, J. L.*; et al.
Journal of Alloys and Compounds, 444-445, p.80 - 83, 2007/10
Times Cited Count:9 Percentile:47.73(Chemistry, Physical)We summarize the results of muon spin relaxation (SR) measurements carried out in- and -Pu and in the superconducting state ofPuCoGa. In Pu metal, interest has centered on whether or not magnetic order exists in the hightemperature fcc phase,The Pu metal studies were designed to search for evidence of magnetic ordering, andhave set the most stringent limits to date for the ordered moment. In PuCoGa the temperature dependence of themagnetic penetration depth (T) was investigated in a fresh sample and again in the same sampleafter 400 days of aging. We find (T) T for T Tc/2, indicating a line of nodes in thesuperconducting order parameter. Remarkably, the temperature dependence of (T) is littlechanged even after significant radiation damage.
Oishi, Kazuki; Heffner, R. H.; Morris, G. D.*; Bauer, E. D.*; Graf, M. J.*; Zhu, J.-X.*; Morales, L. A.*; Sarrao, J. L.*; Fluss, M. J.*; MacLaughlin, D. E.*; et al.
Physical Review B, 76(6), p.064504_1 - 064504_10, 2007/08
Times Cited Count:13 Percentile:50.92(Materials Science, Multidisciplinary)Shu, L.*; MacLaughlin, D. E.*; Aoki, Yuji*; Tsunashima, Yoshino*; Yonezawa, Yuki*; Sanada, Shotaro*; Kikuchi, Daisuke*; Sato, Hideyuki*; Heffner, R. H.; Higemoto, Wataru; et al.
Physical Review B, 76(1), p.014527_1 - 014527_8, 2007/07
Times Cited Count:22 Percentile:65.31(Materials Science, Multidisciplinary)Aoki, Yuji*; Tayama, Takashi*; Sakakibara, Toshiro*; Kuwahara, Keitaro*; Iwasa, Kazuaki*; Kogi, Masafumi*; Higemoto, Wataru; MacLaughlin, D. E.*; Sugawara, Hitoshi*; Sato, Hideyuki*
Journal of the Physical Society of Japan, 76(5), p.051006_1 - 051006_13, 2007/05
Times Cited Count:64 Percentile:56.78(Physics, Multidisciplinary)This review presents a summary and evaluation of the experimental properties of unconventional superconductivity in PrOsSb. After a brief introduction of filled skutterudites, we argue that the normal-state properties of PrOsSb are quite different from ordinary heavy-fermion superconductors.
Oishi, Kazuki; Heffner, R. H.; Morris, G. D.*; Fluss, M. J.*; Bauer, E. D.*; Morales, L. A.*; Sarrao, J. L.*; MacLaughlin, D. E.*; Shu, L.*; Ito, Takashi; et al.
Journal of Magnetism and Magnetic Materials, 310(2, Part1), p.566 - 568, 2007/03
no abstracts in English
Heffner, R. H.; MacLaughlin, D. E.*; Sonier, J. E.*; Fundley, M. F.*; Thompson, J. D.*
Journal of Magnetism and Magnetic Materials, 310(2, Part1), p.e6 - e8, 2007/03
Recently phenomenological picture of the formation of the heavy femion state was put forward in terms of a two-component susceptibility, one component corresponding to non-interacting local moments and second, low-temperature component associated with onset of heavy fermation state (so-called "two-fluid" model). This phenomenology can be studied by measuring the local susceptibility via SR Knight shift measurements. Normally, the Knight shift is proposional to the bulk susceptibility. The onset of second component appears as a deviation in the linear relation. Previously we discovered a non-linear relation in UThBe, which was interpreted in terms of a temperature-dependent hyperfine field. Here we reexamine these data in terms of the two-fluid model. Our analysis shows that these date are consistent with the scaling law proposed. The SR data are discussed in terms of related changes in the resistivity and the NMR relaxation rates in these systems.
Shu, L.*; Higemoto, Wataru; Aoki, Yuji*; Frederick, N. A.*; Yuhasz, W. M.*; Heffner, R. H.; Oishi, Kazuki; Ishida, Kenji*; Kadono, Ryosuke*; Koda, Akihiro*; et al.
Journal of Magnetism and Magnetic Materials, 310(2, Part1), p.551 - 553, 2006/11
Heffner, R. H.; Bauer, E. D.*; Chung, B.*; Fluss, M. J.*; Higemoto, Wataru; Ito, Takashi; MacLaughlin, D. E.*; Morales, L. A.*; Morris, G. D.*; Oishi, Kazuki; et al.
Journal of the Physical Society of Japan, 75(Suppl.), p.14 - 19, 2006/08
no abstracts in English
Heffner, R. H.; Morris, G. D.*; Fluss, M. J.*; Chung, B.*; MacLaughlin, D. E.*; Shu, L.*; Anderson, J. E.*
Physica B; Condensed Matter, 374-375, p.163 - 166, 2006/03
Times Cited Count:8 Percentile:37.60(Physics, Condensed Matter)The SR measurements in pulutonium metals are reported for the first time. The ground-state properties of Pu metal is not understood clearly. We found the upper limits of the ordered moment in -Pu and -stabilized Pu is at 4K.
MacLaughlin, D. E.*; Rose, M. S.*; Anderson, J. E.*; Shu, L.*; Heffner, R. H.; Kimura, Tsuyoshi*; Morris, G. D.*; Bernal, O. O.*
Physica B; Condensed Matter, 374-375, p.142 - 144, 2006/03
Times Cited Count:3 Percentile:17.27(Physics, Condensed Matter)Longitudinal-field muon spin relaxation experiments have been carried out in the paramagnetic state of single-crystal GdTiO just above the phase transition. At high applied fields the relaxation time is proportional to field. At low fields the relaxation rate increases markedly as the freezing temperature is approached. This behavior is consistent with the very long autocorrelation function cutoff time.
MacLaughlin, D. E.*; Rose, M. S.*; Bernal, O. O.*; Heffner, R. H.; Nieuwenhuys, G. J.*; Chau, R.*; Maple, M. B.*
Physica B; Condensed Matter, 374-375, p.174 - 176, 2006/03
Times Cited Count:0 Percentile:0.00(Physics, Condensed Matter)Transverse-field SR shifts and relaxation rates have been measured in the non-Fermi liquid alloy system UCuPt. At low temperatures the fractional spread in Knight shifts is 2 for x=1, but is only half this value for x=1.5 and 2.5. In a disorder-driven scenario where the NFL behavior is due to a broadly distributed characteristic energy E, our results indicate that E/EK/K) is similar for UCuPd. Our results correlate with the observed suppression of other NFL anomaliess.
MacLaughlin, D. E.*; Rose, M. S.*; Anderson, J. E.*; Bernal, O. O.*; Heffner, R. H.; Nieuwenhuys, G. J.*; Baumbach, R. E.*; Butch, N. P.*; Maple, M. B.*
Physica B; Condensed Matter, 374-375, p.177 - 179, 2006/03
Times Cited Count:1 Percentile:6.21(Physics, Condensed Matter)Longitudinal-field SR experiments have been performed in unannealed and annealed samples of the heavy-fermion compound UCuPd to study the effect of disorder on non-Fermi liquid behavior in this material. The observed scaling exponent independent of annealing. Annealed samples exhibited a reduction of the relaxation rate at low temperatures, indicating that annealing shifts fluctuation noise power to higher frequencies. There was no tendency of the inhomogeneous spread in rates to decrease with annealing. The correlation with residual resistivity previously observed for a number of NFL heavy-electron materials is also found in the present work.
Morris, G. D.*; Heffner, R. H.; Bauer, E. D.*; Morales, L. A.*; Sarrao, J. L.*; Fluss, M. J.*; MacLaughlin, D. E.*; Shu, L.*; Anderson, J. E.*
Physica B; Condensed Matter, 374-375, p.180 - 183, 2006/03
Times Cited Count:15 Percentile:55.45(Physics, Condensed Matter)Heffner, R. H.; Morris, G. D.*; Bauer, E. D.*; Sarrao, J. L.*; Thompson, J. D.*; MacLaughlin, D. E.*; Shu, L.*
Physica B; Condensed Matter, 375-375, p.184 - 187, 2006/03
Times Cited Count:6 Percentile:30.40(Physics, Condensed Matter)Heffner, R. H.; Morris, G. D.*; Fluss, M. J.*; Chung, B.*; McCall, S.*; MacLaughlin, D. E.*; Shu, L.*; Oishi, Kazuki; Bauer, E. D.*; Sarrao, J. L.*; et al.
Physical Review B, 73(9), p.094453_1 - 094453_5, 2006/03
Times Cited Count:35 Percentile:77.20(Materials Science, Multidisciplinary)no abstracts in English
MacLaughlin, D. E.*; Shu, L.*; Anderson, J. E.*; Heffner, R. H.; Morris, G. D.*; Bernal, O. O.*; Kim, J. S.*; Stewart, G. R.*
Physica B; Condensed Matter, 378-380, p.144 - 145, 2006/02
Times Cited Count:0 Percentile:0.00(Physics, Condensed Matter)