Lévy F, Sheikin I, Grenier B, Huxley A D
Département de Recherche Fondamentale sur la Matière Condensée, Service de Physique Statistique, Magnétique, et Supraconductivitié, Commissariat àl'Energie Atomique (CEA), Grenoble 38054, France.
Science. 2005 Aug 26;309(5739):1343-6. doi: 10.1126/science.1115498.
In several metals, including URhGe, superconductivity has recently been observed to appear and coexist with ferromagnetism at temperatures well below that at which the ferromagnetic state forms. However, the material characteristics leading to such a state of coexistence have not yet been fully elucidated. We report that in URhGe there is a magnetic transition where the direction of the spin axis changes when a magnetic field of 12 tesla is applied parallel to the crystal b axis. We also report that a second pocket of superconductivity occurs at low temperature for a range of fields enveloping this magnetic transition, well above the field of 2 tesla at which superconductivity is first destroyed. Our findings strongly suggest that excitations in which the spins rotate stimulate superconductivity in the neighborhood of a quantum phase transition under high magnetic field.
在包括URhGe在内的几种金属中，最近观察到超导现象在远低于铁磁态形成温度时出现并与铁磁性共存。然而，导致这种共存状态的材料特性尚未完全阐明。我们报告称，在URhGe中存在一种磁转变，当沿晶体b轴平行施加12特斯拉的磁场时，自旋轴方向会发生变化。我们还报告称，在低温下，围绕这种磁转变的一系列磁场范围内会出现第二个超导能隙，远高于超导首次被破坏时的2特斯拉磁场。我们的研究结果强烈表明，在高磁场下，自旋旋转的激发会在量子相变附近刺激超导性。
