Critical behavior of the magnetic Weyl semimetal PrAlGe

Abstract

Noncentrosymmetric PrAlGe is considered to be a magnetic Weyl semimetal that breaks both time-reversal and inversion symmetry, in which the Weyl nodes can be moved by magnetization. However, the magnetic interaction of this system remains poorly understood. In this work we perform a systematical investigation on magnetic properties and critical behaviors in single-crystal PrAlGe. The temperature, field, and angle dependence of magnetization reveal a strong magnetic anisotropy along the $c$ axis and absolute isotropic characteristic in the $ab$ plane. By fitting to the magnetic entropy change $[\mathrm{\ensuremath{\Delta}}{S}_{M}(T,H)]$ around the critical temperature ${T}_{C}=16$ K, critical exponents $\ensuremath{\beta}=0.136(6), \ensuremath{\gamma}=1.801(7)$, and $\ensuremath{\delta}=14.2(6)$ are obtained. Based on the obtained critical exponents, $\mathrm{\ensuremath{\Delta}}{S}_{M}(T,H)$ and $M(T,H)$ curves are scaled into universality curves under the framework of universality principle. The critical behaviors and exponents suggest that the magnetic interaction in PrAlGe is of a two-dimensional Ising type, revealing a uniaxial magnetic interaction along the $c$ axis. However, the ordering moments are tilted from the $c$ axis, which causes antiferromagnetism in the $ab$ plane. The clarification of the magnetic interaction and magnetic structure is of significance for unveiling its interplay with topological properties in this system.