Unusually strong electronic correlation and field-induced ordered phase in YbCo2
Unusually strong electronic correlation and field-induced ordered phase in YbCo2
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DOI：
10.1088/1361-648x/acca5a
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发表时间：
2023-07-19
影响因子：
2.7
通讯作者：
Mori，T.
中科院分区：
文献类型：
--
作者：
Valenta，J.;Tsujii，N.;Mori，T.
我们报告的电阻率，磁化强度和比热YbCo 2的第一次研究。单相样品的YbCo 2的测量带来的磁有序的证据，在零磁场下降到0.3 K。观察到了近藤低温的表现。比热除以温度C/T，随温度下降到0.3K，比热值在7 J/molK 2以上呈递增趋势，但没有磁有序的迹象，表明存在很大的电子比热.磁比热的分析表明，低温比热的大部分不能简单地解释为低的近藤温度，而是由于在3d和4f电子中的强的位间磁关联。在高达7 T的静磁场下进行了随温度变化的测量，结果表明，在2 T以上的场致相变的演变。转变温度随着磁场的增加而增加，表明其具有铁磁性。外推的转变温度为零场表明，YbCo 2是在量子临界点的非常接近。这些结果表明，在YbCo 2的特殊情况下，Co 3d电子的巡游电子磁性和Yb 4f局域矩量子临界附近的Kondo效应都可能起作用.
We report the first study of electrical resistivity, magnetization, and specific heat on YbCo 2. The measurements on a single-phased sample of YbCo 2 bring no evidence of magnetic ordering down to 0.3 K in a zero magnetic field. The manifestations of low Kondo temperature are observed. The specific heat value divided by temperature, C/T, keeps increasing logarithmically beyond 7 J/mol K 2 with decreasing temperature down to 0.3 K without no sign of magnetic ordering, suggesting a very large electronic specific heat. Analysis of the magnetic specific heat indicates that the large portion of the low-temperature specific heat is not explained simply by the low Kondo temperature but is due to the strong intersite magnetic correlation in both the 3d and 4f electrons. Temperature-dependent measurements under static magnetic fields up to 7 T are carried out, which show the evolution of field-induced transition above 2 T. The transition temperature increases with increasing field, pointing to a ferromagnetic character. The extrapolation of the transition temperature to zero field suggests that YbCo 2 is in the very proximity of the quantum critical point. These results indicate that in the unique case of YbCo 2, the itinerant electron magnetism of Co 3d-electrons and the Kondo effect within the vicinity of quantum criticality of Yb 4f-local moments can both play a role.