论文标题
交换场增强了压缩反铁磁EUTE中超导性的上部临界场
Exchange field enhanced upper critical field of the superconductivity in compressed antiferromagnetic EuTe2
论文作者
论文摘要
我们报告了关于C型抗铁磁半导体EUTE2高达36.0 GPA的高压研究。从I4/MCM到C2/M空间组的结构过渡在〜16 GPA处被鉴定出来。在I4/MCM和C2/M空间组中，超导性在〜5 GPA以上发现。在低压阶段（<16 GPA）中，由于增强的磁交换相互作用，随着压力的增加，抗铁磁过渡温度得到了增强。磁势测量表明EU2+的局部力矩与TE 5P轨道的传导电子之间的相互作用。超导性的上部临界场远高于保利极限。在整个向高压阶段（> 16 GPA）的结构过渡过程中，Eute2变为非磁性，超导过渡温度随着临界场高于Pauli极限的上限而平稳地演变。因此，在低压阶段，Eute2的高临界场是由于欧盟磁序的交换场补偿效应，并且在BCS理论的框架中可能会出现两种结构中的超导性。
We report high pressure studies on the C-type antiferromagnetic semiconductor EuTe2 up to 36.0 GPa. A structural transition from the I4/mcm to C2/m space group is identified at ~16 GPa. Superconductivity is discovered above ~5 GPa in both the I4/mcm and C2/m space groups. In the low-pressure phase (< 16 GPa), the antiferromagnetic transition temperature is enhanced with increasing pressure due to the enhanced magnetic exchange interactions. Magnetoresistance measurements indicate an interplay between the local moments of Eu2+ and the conduction electrons of Te 5p orbits. The upper critical field of the superconductivity is well above the Pauli limit. Across the structural transition to the high-pressure phase (> 16 GPa), EuTe2 becomes nonmagnetic and the superconducting transition temperature evolves smoothly with the upper critical field below the Pauli limit. Therefore, the high upper critical field of EuTe2 in the low-pressure phase is due to the exchange field compensation effect of the Eu magnetic order and the superconductivity in both structures may arise in the framework of the BCS theory.
