Specific heat of CeRhIn5 in high magnetic fields: Magnetic phase diagram revisited
Specific heat of CeRhIn5 in high magnetic fields: Magnetic phase diagram revisited
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DOI：
10.1103/physrevb.103.045110
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发表时间：
2021-01
期刊：
影响因子：
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通讯作者：
S. Mishra;A. Demuer;D. Aoki;I. Sheikin
中科院分区：
文献类型：
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作者：
S. Mishra;A. Demuer;D. Aoki;I. Sheikin
CeRhIn 5是一种典型的反铁磁重费米子化合物，其在磁场中的行为是独特的。施加在四面体晶体结构的基面中的磁场诱导两个额外的相变。当磁场沿沿着或靠近c轴施加时，在B = 30 T处出现一个新的相位，其特征在于显著的面内电子各向异性，远低于临界场Bc ' 50 T，以抑制反铁磁序。这个新相的确切起源，最初被认为是一个电子-电子态，仍然难以捉摸。在这里，我们报告低温比热测量CeRhIn 5在高静磁场高达36 T施加沿着的a和c轴。对于沿着a轴施加的场，我们证实了先前提出的相图，并将其推广到更高的场。这使我们能够观察到一个三相点在1030 T，其中一阶过渡从一个不相称的相称的磁性结构合并到开始的第二阶反铁磁过渡。对于沿沿着c轴施加的场，我们在B处观察到一个小但明显的异常，我们讨论了可能的场诱导跃迁，可能是弱一阶的。我们进一步认为，转变对应于磁结构的变化。我们修订的磁相图CeRhIn 5的两个主要方向的磁场完全基于热力学异常。
CeRhIn5 is a prototypical antiferromagnetic heavy-fermion compound, whose behavior in a magnetic field is unique. A magnetic field applied in the basal plane of the tetragonal crystal structure induces two additional phase transitions. When the magnetic field is applied along, or close to, the c axis, a new phase characterized by a pronounced in-plane electronic anisotropy emerges at B∗ ≈ 30 T, well below the critical field, Bc ' 50 T, to suppress the antiferromagnetic order. The exact origin of this new phase, originally suggested to be an electronic-nematic state, remains elusive. Here we report low-temperature specific heat measurements in CeRhIn5 in high static magnetic fields up to 36 T applied along both the a and c axes. For fields applied along the a axis, we confirmed the previously suggested phase diagram, and extended it to higher fields. This allowed us to observe a triple point at ∼ 30 T, where the first-order transition from an incommensurate to commensurate magnetic structure merges into the onset of the second-order antiferromagnetic transition. For fields applied along the c axis, we observed a small but distinct anomaly at B∗, which we discuss in terms of a possible field-induced transition, probably weakly first-order. We further suggest that the transition corresponds to a change of magnetic structure. We revise magnetic phase diagrams of CeRhIn5 for both principal orientations of the magnetic field based entirely on thermodynamic anomalies.