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arXiv 1002.1924cond-mat.str-el
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反铁磁体CeRh $_2$ Si $_2$的高场变磁性

High-field metamagnetism in the antiferromagnet CeRh$_2$Si$_2$

W. Knafo, D. Aoki, D. Vignolles, B. Vignolle, Y. Klein, C. Jaudet, A. Villaume, C. Proust, J. Flouquet

摘要:

本文研究了反铁磁体CeRh $_2$ Si $_2$在高达50特斯拉的脉冲磁场中的转矩、磁致伸缩和输运以及在高达13特斯拉的静磁场中的热膨胀。从这些测量中推导出CeRh $_2$ Si $_2$的磁场-温度相图,其中磁场沿易磁化轴$\mathbf{c}$施加。二级相变温度$T_{N}$和一级相变温度$T_{1,2}$(零场时分别为~36 K和26 K)随电场的增加而降低。场致反铁磁-顺磁边界线$H_c$在1.5 K时为26 T,从低温时的一阶变为高温时的二阶。磁场-温度相图被发现是由(至少)三个不同的反铁磁相。它们被一阶谱线$H_{1,2}$和$H_{2,3}$分开,前者对应于H=0时的$T_{1,2}$,后者在1.5 K时等于25.5 T。的最大值的$T^2$ -系数$A$的电阻率观察在发病的高场极化制度,这被解释为一个增强的有效质量的签名在场诱导的量子不稳定性。将CeRh $_2$ Si $_2$中$A$系数的磁场依赖性与其压力依赖性进行了比较,并与原型重费米子系统CeRu $_2$ Si $_2$中$A$的场依赖性进行了比较。

英文摘要:

A study of the antiferromagnet CeRh$_2$Si$_2$ by torque, magnetostriction, and transport in pulsed magnetic fields up to 50 Tesla and by thermal expansion in static fields up to 13 Tesla is presented. The magnetic field-temperature phase diagram of CeRh$_2$Si$_2$, where the magnetic field is applied along the easy axis $\mathbf{c}$, is deduced from these measurements. The second-order phase transition temperature $T_{N}$ and the first-order phase transition temperature $T_{1,2}$ (=~36 K and 26 K at zero-field, respectively) decrease with increasing field. The field-induced antiferromagnetic-to-paramagnetic borderline $H_c$, which equals 26 T at 1.5 K, goes from first-order at low temperature to second-order at high temperature. The magnetic field-temperature phase diagram is found to be composed of (at least) three different antiferromagnetic phases. These are separated by the first-order lines $H_{1,2}$, corresponding to $T_{1,2}$ at H=0, and $H_{2,3}$, which equals 25.5 T at 1.5 K. A maximum of the $T^2$-coefficient $A$ of the resistivity is observed at the onset of the high-field polarized regime, which is interpreted as the signature of an enhanced effective mass at the field-induced quantum instability. The magnetic field dependence of the $A$ coefficient in CeRh$_2$Si$_2$ is compared with its pressure dependence, and also with the field dependence of $A$ in the prototypal heavy-fermion system CeRu$_2$Si$_2$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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