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arXiv · 2511.12078

Search for quantum-tricritical-point in antiferromagnet CeRu$_2$(Si$_{1-x}$Ge$_x$)$_2$

H. Shinya·F. Ito·N. Kabeya·Y. Mizukami·N. Kimura
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Abstract

CeRu$_2$Si$_2$ is a well-known heavy fermion paramagnet, and substituting Ge for Si induces antiferromagnetism. This antiferromagnetism is Ising-like and has a tricritical point in the magnetic field ($H$) -temperature ($T$) phase diagram. Since the temperature of the tricritical point is expected to decrease with increasing pressure ($P$), we investigated the pressure dependence of the magnetic phase transitions. We determined the $H$-$P$ phase diagram and revealed that a first-order phase-transition line changes to a quantum critical line, which implies the existence of the quantum tricritical point. A ferromagnetic quantum fluctuation arises in the vicinity of the possible quantum tricritical point.

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H. Shinya, F. Ito, N. Kabeya, Y. Mizukami, N. Kimura. 2025-11-15. Search for quantum-tricritical-point in antiferromagnet CeRu$_2$(Si$_{1-x}$Ge$_x$)$_2$. https://arxiv.org/abs/2511.12078

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