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Evidence for weak spin-orbit interaction experienced by Cooper pairs in the spin-triplet superconductor UPt$$_3$$; $$^{195}$$Pt-NMR study

青山 泰介*; 小手川 恒*; 木村 憲彰*; 山本 悦嗣; 芳賀 芳範; 大貫 惇睦*; 藤 秀樹*

Journal of the Physical Society of Japan, 88(6), p.064706_1 - 064706_7, 2019/06

$$^{195}$$Pt-NMR measurements under magnetic field ($$H$$) parallel to the $$c$$-axis in the vicinity of the upper critical field $$H_{rm c2}$$ have been carried out on the heavy-fermion superconductor UPt$$_3$$. The quasiparticle spin susceptibility was obtained from the measurements. The field dependence of the susceptibility suggests that the $$d$$-vector freely rotates in magnetic field. It is therefore concluded that spin-orbit interaction, which confines the direction of the $$d$$-vector with respect to the crystal axis, is weak in UPt$$_3$$.


Electronic structure in heavy fermion compound UPd$$_2$$Al$$_3$$ through directional Compton profile measurement

小泉 昭久*; 久保 康則*; 山本 悦嗣; 芳賀 芳範; 櫻井 吉晴*

Journal of the Physical Society of Japan, 88(3), p.034714_1 - 034714_6, 2019/03

 パーセンタイル:100(Physics, Multidisciplinary)

Directional Compton profiles of a heavy fermion compound UPd$$_2$$Al$$_3$$ are measured in the basal plane of the hexagonal lattice. A remarkable change of the two-dimensional electron occupation number densities has been observed between 20 K and 100 K. Obtained results are attributed to the modification of the 5$$f$$ electronic states.


Online chemical adsorption studies of Hg, Tl, and Pb on SiO$$_{2}$$ and Au surfaces in preparation for chemical investigations on Cn, Nh, and Fl at TASCA

Lens, L.*; Yakushev, A.*; D$"u$llmann, Ch. E.*; 浅井 雅人; Ballof, J.*; Block, M.*; David, H. M.*; Despotopulos, J.*; Di Nitto, A.*; Eberhardt, K.*; et al.

Radiochimica Acta, 106(12), p.949 - 962, 2018/12

 パーセンタイル:100(Chemistry, Inorganic & Nuclear)

半減期4$$sim$$49秒の短寿命同位体を用いて、水銀(Hg), タリウム(Tl), 鉛(Pb)の単一原子レベルでのSiO$$_{2}$$及びAu表面への固体吸着挙動をオンライン気相実験により調べた。超重元素Cn, Nh, Flの吸着エンタルピー測定のためのモデル実験として実施した。短寿命同位体はドイツ重イオン研究所の反跳核分離装置TASCAを用いて生成・分離した。生成核はヘリウムガス中に捕集された後、SiO$$_{2}$$あるいはAuで表面を覆われたSi検出器で作製されたガスクロマトグラフィーカラムへと導入した。短寿命Tl及びPb同位体は室温においてSiO$$_{2}$$表面に吸着し、Si検出器で測定することに成功した。一方、HgはSiO$$_{2}$$表面には吸着せず、Au表面に吸着した。この結果より、本実験のセットアップを用いることで短寿命Hg, Tl, Pb同位体の吸着特性を調べることができると証明され、この手法がCn, Nh, Flの実験にも適用できることが確認された。


Magnetic field induced phenomena in UIrGe in fields applied along the $$b$$ axis

Posp$'i$$v{s}$il, J.*; 芳賀 芳範; 小濱 芳允*; 三宅 厚志*; 神戸 振作; 立岩 尚之; Vali$v{s}$ka, M.*; Proschek, P.*; Prokle$v{s}$ka, J.*; Sechovsk$'y$, V.*; et al.

Physical Review B, 98(1), p.014430_1 - 014430_7, 2018/07

 被引用回数:1 パーセンタイル:59.26(Materials Science, Multidisciplinary)

The metamagnetic transition between the antiferromagnetic and paramagnetic state in UIrGe has been studied at various temperatures by magnetization, heat capacity, and magnetocaloric effect measurements on a single crystal in static and pulsed magnetic fields applied along the orthorhombic $$b$$ axis. The first-order transition is accompanied by a dramatic increase of the Sommerfeld coefficient. A tentative scenario explaining these anomalies by antiferromagnetic correlations or short-range order in the paramagnetic state is discussed.


Electronic states in EuCu$$_2$$(Ge$$_{1-x}$$Si$$_x$$)$$_2$$ based on the doniach phase diagram

伊覇 航*; 屋良 朝之*; 安次富 洋介*; 垣花 将司*; 竹内 徹也*; 本多 史憲*; 仲村 愛*; 青木 大*; 郷地 順*; 上床 美也*; et al.

Journal of the Physical Society of Japan, 87(6), p.064706_1 - 064706_14, 2018/06

 被引用回数:2 パーセンタイル:29.91(Physics, Multidisciplinary)

We succeeded in growing single crystals of the series of EuCu$$_2$$(Ge$$_{1-x}$$Si$$_x$$)$$_2$$ compounds.Physical property measurements demonstrate a maximum of the antiferromagnetic transition temperature appears at $$x = 0.5$$. Antiferromagnetism then disappears around $$x = 0.7$$ followed by a heavy-fermion formation at higher concentrations. These observations follow the Doniach phase diagram as a function of $$x$$.


Temperature of thermal spikes induced by swift heavy ions

松崎 勝太*; 林 宏明*; 中嶋 薫*; 松田 誠; 左高 正雄*; 辻本 将彦*; Toulemonde, M.*; 木村 健二*

Nuclear Instruments and Methods in Physics Research B, 406(Part B), p.456 - 459, 2017/09

Few-nm sized gold, platinum and palladium nanoparticles were deposited on amorphous silicon nitride films. These films were irradiated with 420 MeV Au and 100 MeV Xe ions. Temperature distributions of thermal spikes produced by these ions were evaluated by observing desorption of the nanoparticles from the target surfaces upon ion impact. It was found that the temperature of the thermal spike produced by 420 MeV Au is higher than 100 MeV Xe. The observed temperature of the thermal spike at the entrance surface is slightly lower than that at the exit surface both for 420 MeV Au and 100 MeV Xe ions. These results can be well explained by the inelastic thermal spike model.


Atomic-scale visualization of surface-assisted orbital order

Kim, H.*; 吉田 靖雄*; Lee, C.-C.*; Chang, T.-R.*; Jeng, H.-T.*; Lin, H.*; 芳賀 芳範; Fisk, Z.*; 長谷川 幸雄*

Science Advances (Internet), 3(9), p.eeao0362_1 - eeao0362_5, 2017/09

We report a first, real-space, imaging of an orbital ordered structure on a cobalt-terminated surface of the well-studied heavy fermion compound CeCoIn$$_5$$. Within small tip-sample distances, the cobalt atoms on a cleaved (001) surface take on dumbbell shapes alternatingly aligned in the [100] and [010] directions in scanning tunneling microscopy topographies. First-principles calculations reveal that this staggered orbital order is triggered by enhanced on-site Coulomb interaction at the surface.


Studies of high density baryon matter with high intensity heavy-ion beams at J-PARC

佐甲 博之; 原田 寛之; 坂口 貴男*; 中條 達也*; 江角 晋一*; 郡司 卓*; 長谷川 勝一; Hwang, S.; 市川 裕大; 今井 憲一; et al.

Nuclear Physics A, 956, p.850 - 853, 2016/12

 被引用回数:7 パーセンタイル:26.65(Physics, Nuclear)

We are designing a large acceptance heavy-ion spectrometer at J-PARC based on a Toroidal magnet to measure hadrons, lepton pairs, and event-by-event fluctuations. We are also designing a closed geometry spectrometer to measure hypernuclei to study weak decays and magnetic moments. In this presentation, the preliminary version of the designed acceleration scheme, as well as the spectrometers and their expected performance and physics results are presented.


Fermi surface of ThRu$$_{2}$$Si$$_{2}$$ as a reference to the strongly correlated isostructural metals investigated by quantum oscillations

松本 裕司*; 芳賀 芳範; 立岩 尚之; 青木 晴善*; 木村 憲彰*; 山村 朝雄*; 山本 悦嗣; 松田 達磨*; Fisk, Z.*; 山上 浩志*

Journal of the Physical Society of Japan, 85(10), p.104709_1 - 104709_7, 2016/10

 被引用回数:2 パーセンタイル:63.85(Physics, Multidisciplinary)

dHvA oscillations were detected on an actinide compound ThRu$$_2$$Si$$_2$$ which is regarded as a reference to strongly correlated electron systems URu$$_2$$Si$$_2$$ and CeRu$$_2$$Si$$_2$$. Observed Fermi surfaces well coincides with the band structure calculations, as well as experimentally obtained ones for a heavy fermion compound CeRu$$_2$$Si$$_2$$. On the other hand, Fermi surfaces of URu$$_2$$Si$$_2$$ have significantly different characteristics, suggesting an itinerant ground state of 5f electrons.


Unusual pressure evolution of the Meissner and Josephson effects in the heavy-fermion superconductor UPt$$_3$$

郷地 順*; 住山 昭彦*; 山口 明*; 本山 岳*; 木村 憲彰*; 山本 悦嗣; 芳賀 芳範; 大貫 惇睦

Physical Review B, 93(17), p.174514_1 - 174514_5, 2016/05

 被引用回数:1 パーセンタイル:88.02(Materials Science, Multidisciplinary)

The Josephson effect between a single crystal UPt$$_3$$ and a conventional superconductor Al has been investigated under pressure. A possible change of the superconducting order parameter has been detected at a critical $$P_c$$ where the symmetry-breaking antiferromagnetic order disappears. The conclusion is also supported by the different behaviors observed in Josephson current and penetration depth.


Vacuum chromatography of Tl on SiO$$_{2}$$ at the single-atom level

Steinegger, P.*; 浅井 雅人; Dressler, R.*; Eichler, R.*; 金谷 佑亮*; 水飼 秋菜*; 永目 諭一郎; Piguet, D.*; 佐藤 哲也; Sch$"a$del, M.; et al.

Journal of Physical Chemistry C, 120(13), p.7122 - 7132, 2016/04

 被引用回数:8 パーセンタイル:42.61(Chemistry, Physical)



Evidence for chiral $$d$$-wave superconductivity in URu$$_2$$Si$$_2$$ from the field-angle variation of its specific heat

橘高 俊一郎*; 清水 悠晴*; 榊原 俊郎*; 芳賀 芳範; 山本 悦嗣; 大貫 惇睦; 堤 康雅*; 野本 拓也*; 池田 浩章*; 町田 一成*

Journal of the Physical Society of Japan, 85(3), p.033704_1 - 033704_4, 2016/03

 被引用回数:19 パーセンタイル:10.97(Physics, Multidisciplinary)

Low-energy quasiparticle excitations in the heavy-fermion superconductor URu$$_2$$Si$$_2$$ were investigated by specific heat measurements as a function of temperature, magnetic field and its angle. Experimental results agree with the theoretical model for a superconducting gap with chiral $$d$$-wave symmetry.


Tungsten impurity density in fusion plasma

仲野 友英; Shumack, A.*; Maggi, C. F.*

Journal of Physics B; Atomic, Molecular and Optical Physics, 2 Pages, 2016/01



Magnetic anisotropy and thermodynamic anomaly in the superconducting mixed state of UBe$$_{13}$$ probed by static dc magnetization measurements

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:7 パーセンタイル:43.79(Materials Science, Multidisciplinary)

Static dc magnetization measurements were performed for a heavy fermion superconductor UBe$$_{13}$$ single crystal. For the fields along the [100] and [110] directions of cubic lattice, a magnetic anomaly was found at a characteristic field $$H_{rm Mag}^{*}$$ 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.


Surface modifications of hydrogen storage alloy by heavy ion beams with keV to MeV irradiation energies

阿部 浩之; 徳平 真之介*; 内田 裕久*; 大島 武

Nuclear Instruments and Methods in Physics Research B, 365(Part A), p.214 - 217, 2015/12



Simulation study of radial dose due to the irradiation of a swift heavy ion aiming to advance the treatment planning system for heavy particle cancer therapy; The Effect of emission angles of secondary electrons

森林 健悟

Nuclear Instruments and Methods in Physics Research B, 365(Part B), p.592 - 595, 2015/12

Aiming to advance the treatment planning system for heavy particle cancer therapy and to study cluster DNA damage, we have been developing a simulation model for radial dose due to the irradiation of a heavy ion. Now, two types of radial dose distributions have been available in the treatment planning system for heavy particle cancer therapy. However, these distributions had been developed without the detailed examinations of physical phenomena that occur near the trajectory of an incident ion, though this region is important to estimate the cell survival. The progress of computers allows us to execute such detailed examinations through simulations and to obtain radial dose closer to reality. We compare radial dose distribution obtained from our simulations with the conventional distributions and we suggest which conventional ones should be selected according to incident ion energies. Our simulation model, which has become possible in this century, is the only way to examine physical phenomena that occurs near the trajectory of an incident ion now as far as we know.


Nuclear structure of elements with $$100 le Z le 109$$ from alpha spectroscopy

浅井 雅人; He${ss}$berger, F. P.*; Lopez-Martens, A.*

Nuclear Physics A, 944, p.308 - 332, 2015/12

 被引用回数:24 パーセンタイル:5.74(Physics, Nuclear)

$$alpha$$崩壊核分光による原子番号100から109までの原子核の核構造研究についてレビューした。$$alpha$$崩壊核分光に関わる分離技術やデジタルエレクトロニクスの利用、$$alpha$$線スペクトルにおけるサム効果などの実験技術や実験手法について詳しく記述した。実験結果や物理の議論については、ここ10年間に最も進展のあった、原子番号が偶数で中性子数151, 153, 155を持つ一連の原子核の核構造の系統性に特に焦点を絞って紹介した。


Crossover phase diagram and electronic state in the heavy-fermion metamagnets UIr$$_2$$Zn$$_{20}$$ and UCo$$_2$$Zn$$_{20}$$

広瀬 雄介*; 竹内 徹也*; 本多 史憲*; 吉内 伸吾*; 萩原 政幸*; 山本 悦嗣; 芳賀 芳範; 摂待 力生*; 大貫 惇睦

Journal of the Physical Society of Japan, 84(7), p.074704_1 - 074704_10, 2015/07

 被引用回数:5 パーセンタイル:43.76(Physics, Multidisciplinary)

Magnetic phase diagram of two heavy fermion metamagnets UIr$$_2$$Zn$$_{20}$$ and UCo$$_2$$Zn$$_{20}$$ is investigated. UIr$$_2$$Zn$$_{20}$$ shows a reconstruction of the electronic states across the metamagnetic crossover. However, UCo$$_2$$Zn$$_{20}$$ shows a rather continuous evolution. The remarkable difference in both compounds can be accounted for by different degree of hybridization between 5$$f$$ and ligand electrons.


Performance of new gas-filled recoil ion separator GARIS-II for asymmetric fusion reaction

加治 大哉*; 森本 幸司*; 若林 泰生*; 武山 美麗*; 山木 さやか*; 田中 謙伍*; 羽場 宏光*; Huang, M.*; 村上 昌史*; 金谷 淳平*; et al.

JPS Conference Proceedings (Internet), 6, p.030107_1 - 030107_4, 2015/06



Magnetic and electronic properties of URu$$_2$$Si$$_2$$ revealed by comparison with nonmagnetic references ThRu$$_2$$Si$$_2$$ and LaRu$$_2$$Si$$_2$$

江見 直哉*; 濱端 良輔*; 中山 大将*; 三木 俊宙*; 小山 岳秀*; 上田 光一*; 水戸 毅*; 小堀 洋*; 松本 裕司*; 芳賀 芳範; et al.

Journal of the Physical Society of Japan, 84(6), p.063702_1 - 063702_4, 2015/06

 被引用回数:9 パーセンタイル:31.29(Physics, Multidisciplinary)

NMR/NQR measurements have been carried out on ThRu$$_2$$Si$$_2$$ and LaRu$$_2$$Si$$_2$$ which are the nonmagnetic references of the heavy fermion URu$$_2$$Si$$_2$$. Ru-NQR measurements suggest the relatively close electronic configuration between ThRu$$_2$$Si$$_2$$ and URu$$_2$$Si$$_2$$ at high temperature. However, significant delocalization was observed in URu$$_2$$Si$$_2$$ at low temperatures. Si-NMR experiments on URu$$_2$$Si$$_2$$ revealed Ising-like spin fluctuations in the hidden-order state.

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