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青木 大*; Taupin, M.*; Paulsen, C.*; Hardy, F.*; Taufour, V.*; 小手川 恒*; Hassinger, E.*; Malone, L.*; 松田 達磨; 三宅 厚志*; et al.
Journal of the Physical Society of Japan, 81(Suppl.B), p.SB002_1 - SB002_6, 2012/12
被引用回数:3 パーセンタイル:26.68(Physics, Multidisciplinary)We review our recent studies on ferromagnetic superconductors, UGe2, URhGe, and UCoGe. We focus on experimental results of URhGe and UCoGe in which the superconductivity occurs already at ambient pressure. The huge upper critical field on UCoGe for the field along the hard magnetization axis (-axis) is confirmed by the AC susceptibility measurements by the fine tuning of field angle. Contrary to the huge along the hard-magnetization axis, along the easy-magnetization axis (-axis) is relatively small in value. However, the initial slope of , namely / (0) both in UCoGe and in URhGe indicates the large value, which can be explained by the magnetic domain effect detected in the magnetization measurements. The specific heat measurements using a high quality single crystal of UCoGe demonstrate the bulk superconductivity, which is extended under magnetic field for the field along -axis.
Flouquet, J.*; 青木 大*; Bourdarot, F.*; Hardy, F.*; Hassinger, E.*; Knebel, G.*; 松田 達磨; Maingast, C.*; Paulsen, C.*; Taufour, V.*
Journal of Physics; Conference Series, 273, p.012001_1 - 012001_25, 2011/02
被引用回数:15 パーセンタイル:95.16(Physics, Condensed Matter)A brief review on major advances in heavy fermion physics is presented including the Ce metal phase diagram, the huge effective mass detected in CeAl, and the successive discoveries of unconventional superconductivity in CeCuSi and three U based compounds, UBe, UPt and URuSi. In order to track the origin of the huge effective mass, the case of intermediate valence compounds is discussed with emphasis on the differences between Yb and Ce materials. Pressure and magnetic-field studies on the ferromagnetic superconductor URhGe illustrate the role of the singular effective mass enhancement on the superconducting pairing.
Dvorak, J.*; Brchle, W.*; Chelnokov, M.*; Dllmann, Ch. E.*; Dvorakova, Z.*; Eberhardt, K.*; Jger, E.*; Krcken, R.*; Kuznetsov, A.*; 永目 諭一郎; et al.
Physical Review Letters, 100(13), p.132503_1 - 132503_4, 2008/04
Cm+Mg反応で生成する108番元素ハッシウム(Hs)同位体の生成断面積を迅速気相化学分離装置COMPACTを用いて測定した。入射重イオンMgのエネルギーを変化させCm(Mg, )反応の励起関数を求めたところ、比較的軽い重イオンとアクチノイドターゲットを組合せた反応、いわゆるHot-fusion反応での3蒸発過程が初めて観測された。この蒸発過程で生成する新しい超重核種Hsを同定することに成功した。
Dvorak, J.*; Brchle, W.*; Chelnokov, M.*; Dllmann, Ch. E.*; Dvorakova, Z.*; Eberhardt, K.*; Jger, E.*; Krcken, R.*; Kuznetsov, A.*; 永目 諭一郎; et al.
Physical Review Letters, 100(13), p.132503_1 - 132503_4, 2008/04
被引用回数:125 パーセンタイル:94.91(Physics, Multidisciplinary)By using the complete fusion reaction Mg+Cm, superheavy nuclide Hs was produced in the 3 evaporation channel. The experiment was carried out at UNILAC in GSI, Darmstadt, Germany. The fusion products were separated from other reaction products by using an online chemical separation and detection system. The new isotope Hs (Z=108) was identified by its decay properties and excitation functins as function of bombading energy of Mg, where excitation functions for 4 and 5 channel isotopes Hs were also observed. The Hs was produced at bombarding energy well below the Bass barrier. Because of the prolate deformation of U, Coulomb barrier decreases at polar collisions, allowing the system to fuse even in sub-barrier energies.
Dvorak, J.*; Brchle, W.*; Chelnokov, M.*; Dressler, R.*; Dllmann, Ch. E.*; Eberhardt, K.*; Gorshkov, V.*; Jger, E.*; Krcken, R.*; Kuznetsov, A.*; et al.
Physical Review Letters, 97(24), p.242501_1 - 242501_4, 2006/12
被引用回数:152 パーセンタイル:96.03(Physics, Multidisciplinary)超重核領域で理論的に予想されていた変形した二重魔法核Hsを初めて実験的に確認した。実験はドイツ重イオン研究所(GSI)で行った。Cm+Mg反応で合成されたHs同位体を、迅速気相化学分離法で選択に分離し、壊変エネルギーとそれに伴う15事象の壊変連鎖からHsを同定した。また壊変エネルギーから値をと決定した。Hsの生成断面積は約3pbであった。