INAC/SPSMS, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble, France.
Phys Rev Lett. 2010 Nov 19;105(21):217201. doi: 10.1103/PhysRevLett.105.217201. Epub 2010 Nov 15.
Precise resistivity measurements on the ferromagnetic superconductor UGe2 under pressure p and magnetic field H reveal a previously unobserved change of the anomaly at the Curie temperature. Therefore, the tricritical point (TCP) where the paramagnetic-to-ferromagnetic transition changes from a second order to a first order transition is located in the p-T phase diagram. Moreover, the evolution of the TCP can be followed under the magnetic field in the same way. It is the first report of the boundary of the first order plane which appears in the p-T-H phase diagram of weak itinerant ferromagnets. This line of critical points starts from the TCP and will terminate at a quantum critical point. These measurements provide the first estimation of the location of the quantum critical point in the p-H plane and will inspire similar studies of the other weak itinerant ferromagnets.
对加压 p 和磁场 H 下的铁磁超导体 UGe2 进行的精确电阻率测量揭示了居里温度处异常的先前未观察到的变化。因此，顺磁-铁磁转变从二级相变变为一级相变的临界点 (TCP) 位于 p-T 相图中。此外，同样可以在磁场下跟踪 TCP 的演变。这是首次在弱巡游铁磁体的 p-T-H 相图中报告一级面的边界。这条临界点线始于 TCP，并将在量子临界点处终止。这些测量提供了在 p-H 平面中量子临界点位置的首次估计，并将激发对其他弱巡游铁磁体的类似研究。
