Magnetic anisotropy and critical behavior of the quaternary van der Waals ferromagnetic material $\bf CrGe_{\delta}Si_{1-\delta}Te_3$

TL;DR

This study introduces a new quaternary van der Waals ferromagnetic material, CrGeδSi1−δTe3, showing how Ge substitution affects its magnetic properties and critical behavior, aligning with a 2D Ising model with specific interaction decay.

Contribution

The paper reports the synthesis and characterization of a novel CrGeδSi1−δTe3 material, revealing how Ge substitution influences its lattice, Curie temperature, and magnetic anisotropy, and analyzes its critical behavior.

Findings

Ge substitution increases Curie temperature

Magnetic anisotropy is reduced by Ge substitution

Critical exponents align with 2D Ising model

Abstract

Recently, two-dimensional ferromagnetism in the family of Chromium compounds $\rm CrXTe_3 (X=Si, Ge)$ has attracted a broad research interest. Despite the structural similarity in $\rm CrTe_6$ octahedra, the size effect of inserted Ge or Si dimer contributes to significant differences in magnetism. Here, we report a new quaternary van der Waals ferromagnetic material $\rm CrGe_{\delta}Si_{1-\delta}Te_3$ synthesized by flux method. Ge substitution in Si site results in the lattice expansion, further increasing the Curie temperature and reducing the magnetic anisotropy. The critical behavior of $\rm Cr_{0.96}Ge_{0.17}Si_{0.82}Te_3$ has been studied by specific heat as well as magnetization measurements. And the extracted critical exponents are self-consistent and well-obeying the scaling laws, which are closer to the 2D Ising model with interaction decaying as $J(r)\approx r^{-3.44}$.