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

Abstract

Recently, two-dimensional ferromagnetism in the family of Chromium compounds CrXTe3(X = Si, Ge) has attracted a broad research interest. Despite the structural similarity in CrTe6 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 CrGe δ Si 1−δ Te3 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 Cr0.96Ge0.17Si0.82Te3 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) ≈ r −3.44 .