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清水 悠晴*; 芳賀 芳範; 柳澤 達也*; 網塚 浩*
Physical Review B, 93(2), p.024502_1 - 024502_8, 2016/01
被引用回数:8 パーセンタイル:39.3(Materials Science, Multidisciplinary)Static dc magnetization measurements were performed for a heavy fermion superconductor UBe single crystal. For the fields along the [100] and [110] directions of cubic lattice, a magnetic anomaly was found at a characteristic field
within the superconducting mixed state. It was also found that magnetic anisotropy became more significant above this field. The present study shows that the thermodynamic property of superconductivity changes as a function of magnetic field.
清水 悠晴*; 芳賀 芳範; 柳澤 達也*; 網塚 浩*; 青木 大*; Brison, J.-P.*; Braithwaite, D.*
JPS Conference Proceedings (Internet), 3, p.015009_1 - 015009_6, 2014/06
Static DC magnetization measurements were performed in order to investigate magnetic response of the unconventional superconducting state of UBe. An unusual anomaly was observed inside the superconducting mixed state corresponding either to a peculiarity of superconducting diamagnetism or the anomalous vortex core structures.
田端 千紘*; 稲見 俊哉; 道村 真司*; 横山 淳*; 日高 宏之*; 柳澤 達也*; 網塚 浩*
Philosophical Magazine, 94(32-33), p.3691 - 3701, 2014/00
被引用回数:15 パーセンタイル:59.71(Materials Science, Multidisciplinary)We performed synchrotron X-ray diffraction measurements on a small single crystal of URuSi
. A backscattering diffraction setup (2
) in combination with a Si(6 6 0) monochromator ensures a high instrumental resolution of
, where
denotes a lattice-plane spacing and
is its spread expressed as the full width at half maximum (FWHM). We carefully measured the (5 5 0) Bragg peak in the temperature range between 5 and 25 K, and found it to show no signature of broadening and splitting when "Hidden Order (HO)" sets in below 17.5 K. Temperature variation of the peak position closely follows the behaviour of the known linear thermal expansion coefficient. Detailed analysis of the peak width reveals that the tetragonal fourfold rotational symmetry of URu
Si
is conserved in HO within the experimental accuracy of the orthorhombicity of
.
清水 悠晴*; 芳賀 芳範; 池田 陽一*; 柳澤 達也*; 網塚 浩*
Physical Review Letters, 109(21), p.217001_1 - 217001_5, 2012/11
被引用回数:17 パーセンタイル:68.02(Physics, Multidisciplinary)Precise dc magnetization measurements were performed on a heavy fermion superconductor UBe. We observed a magnetic anomaly in the superconducting mixed state, implying an unusual superconducting state. The origin of the anomaly is discussed based on an unusual superconducting response or a peculiar normal-state magnetization at the vortex cores.
清水 悠晴*; 池田 陽一*; 若林 琢巳*; 芳賀 芳範; 天谷 健一*; 日高 宏之*; 柳澤 達也*; 網塚 浩*
Journal of the Physical Society of Japan, 80(9), p.093701_1 - 093701_4, 2011/09
被引用回数:8 パーセンタイル:51.36(Physics, Multidisciplinary)Low-temperature specific heat measurements under magnetic field were performed on a single crystal UBe. The specific heat shows a
behavior below
0.7
, where
is the superconducting transition temperature, suggesting the existence of point nodes in the superconducting gap. Together with the isotropic behavior of the upper critical magnetic field, the symmetry of the Cooper paring is discussed.
清水 悠晴*; 池田 陽一*; 若林 琢巳*; 天谷 健一*; 芳賀 芳範; 日高 宏之*; 柳澤 達也*; 網塚 浩*
Journal of the Physical Society of Japan, 80(Suppl.A), p.SA100_1 - SA100_3, 2011/07
被引用回数:1 パーセンタイル:11.5(Physics, Multidisciplinary)Low-temperature specific heat and static dc magnetization measurements have been performed in the superconducting state of the heavy-fermion compound UBe. The superconducting phase diagram was obtained from these measurements. We obtained Ginzburg-Landau parameter as a function of temperature and showed that a paramagnetic effect is present down to 0.5 K.
柳澤 達也*; 立岩 尚之; 真山 太一*; 齋藤 旬*; 日高 宏之*; 網塚 浩*; 芳賀 芳範; 根本 祐一*; 後藤 輝孝*
Journal of the Physical Society of Japan, 80(Suppl.A), p.SA105_1 - SA105_3, 2011/07
被引用回数:3 パーセンタイル:28(Physics, Multidisciplinary)Ultrasonic measurements of UPd
Si
were performed in order to investigate elastic properties of the cage-structured compound U
Pd
Si
. At temperatures over antiferromagnetic ordering at
= 19 K, neither an up-turn anomaly nor frequency dependence of the elastic constants, regarding the ultrasonic dispersion (UD), was found. A drastic change of
mode at
, in particular, implies a strong magneto-elastic coupling of 5
-electrons or a possible contribution of a ferroquadrupole interaction to the antiferromagnetism in U
Pd
Si
.
清水 悠晴*; 池田 陽一*; 若林 琢巳*; 天谷 健一*; 芳賀 芳範; 日高 宏之*; 柳澤 達也*; 網塚 浩*
Journal of Physics; Conference Series, 273, p.012084_1 - 012084_4, 2011/02
被引用回数:3 パーセンタイル:63.7Static dc magnetization measurements in the superconducting mixed state of a single crystal UBe were performed by means of a capacitance Faraday-force method down to 0.24 K. Below the upper critical field
, not only a peak effect but also an additional broad anomaly have been observed in magnetization curves. We report superconducting phase diagram of UBe
obtained by our magnetization measurements, including these anomalies.
Shu, L.*; MacLaughlin, D. E.*; 青木 勇二*; 綱島 慶乃*; 米澤 祐樹*; 真田 祥太郎*; 菊地 大輔*; 佐藤 英行*; Heffner, R. H.; 髭本 亘; et al.
Physical Review B, 76(1), p.014527_1 - 014527_8, 2007/07
被引用回数:21 パーセンタイル:65.24(Materials Science, Multidisciplinary)Zero- and longitudinal-field muon spin relaxation experiments have been carried out in the alloy series Pr(OsRu
)
Sb
and Pr
La
Os
Sb
to elucidate the anomalous dynamic muon spin relaxation observed in these materials. The damping rate
associated with this relaxation varies with temperature, applied magnetic field, and dopant concentrations
and
in a manner consistent with the "hyperfine enhancement" of
Pr nuclear spins. This mechanism arises from Van Vleck-like admixture of magnetic Pr
crystalline-electric-field-split excited states into the nonmagnetic singlet ground state by the nuclear hyperfine coupling, thereby increasing the strengths of spin-spin interactions between
Pr and muon spins and within the
Pr spin system. We find qualitative agreement with this scenario and conclude that electronic spin fluctuations are not directly involved in the dynamic muon spin relaxation.