Novel phase diagram of superconductivity and ferromagnetism in UGe2: a 73Ge-NQR study under high pressure
Novel phase diagram of superconductivity and ferromagnetism in UGe2: a 73Ge-NQR study under high pressure
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DOI：
10.1088/0953-8984/17/11/030
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发表时间：
2005-03
期刊：
影响因子：
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通讯作者：
Y. Kitaoka;H. Kotegawa;A. Harada;S. Kawasaki;Y. Kawasaki;Y. Haga;E. Yamamoto;Y. Ōnuki;K. Itoh;E. Haller;H. Harima
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文献类型：
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作者：
Y. Kitaoka;H. Kotegawa;A. Harada;S. Kawasaki;Y. Kawasaki;Y. Haga;E. Yamamoto;Y. Ōnuki;K. Itoh;E. Haller;H. Harima
本文报道了在压力（P）下，通过73 Ge-NQR测量，在巡游铁磁体UGe_2中发现的压力诱导的铁磁性（FM）和超导性（SC）的新相。NQR谱的P依赖性指向从强到弱极化铁磁相（SP和WP）在GPa的临界压力附近的一阶转变。此外，它显示了在GPa附近的铁磁相和顺磁相的相分离。SC表现出的超导转变温度K在GPa的最大值被发现发生在与P-诱导的一级转变从SP到WP。核自旋晶格弛豫速率1/T1的测量探测了铁磁转变，在居里温度处呈现出峰值，并且在Tsc以下没有相干峰的情况下降低。这些结果揭示了FM和非常规SC的一致共存相位与线节点间隙。在Pc附近FM消失的地方，它表明SC发生在FM的背景下，而不是在顺磁相中。我们评论SC的发病和SP和WP的电子状态之间的密切相互作用。
We report on the pressure-induced novel phases of ferromagnetism (FM) and superconductivity (SC) in the itinerant ferromagnet UGe2 through 73Ge-NQR measurements under pressure (P). The P dependence of the NQR spectrum points to a first-order transition from strongly to weakly polarized ferromagnetic phases (SP and WP) around a critical pressure of GPa. Furthermore, it shows the phase separation into the ferromagnetic and paramagnetic phases around GPa. SC exhibiting a maximum value of the superconducting transition temperature K at GPa was found to take place in connection with a P-induced first-order transition from SP to WP. The measurement of nuclear spin lattice relaxation rate 1/T1 has probed the ferromagnetic transition, exhibiting a peak at the Curie temperature as well as a decrease without the coherence peak below Tsc. These results reveal the uniformly coexistent phase of FM and unconventional SC with a line-node gap. Around Pc where the FM disappears, it is shown that SC occurs under the background of FM, but not in the paramagnetic phase. We remark on an intimate interplay between the onset of SC and the underlying electronic state for SP and WP.