Experimental and Computational Insights Into the Magnetic Anisotropy and Magnetic Behaviour of Layered Room-Temperature Ferromagnet Cr$_{1.38}$Te$_2$

TL;DR

This study combines experimental and computational methods to analyze the magnetic anisotropy, critical behavior, and magnetocaloric effect of the layered ferromagnet Cr$_{1.38}$Te$_2$, revealing complex magnetic interactions and potential for magnetic applications.

Contribution

It provides new insights into the magnetic interactions, anisotropy, and critical phenomena of Cr$_{1.38}$Te$_2$, integrating experimental data with Monte-Carlo simulations and density functional theory calculations.

Findings

Critical exponents are self-consistent and match Monte-Carlo simulations.

Magnetocrystalline anisotropy energy density varies with temperature.

Maximum entropy change near the Curie temperature is approximately 2.51 J/kg-K.

Abstract

We investigate the structural, magnetocrystalline anisotropy, critical behaviour, and magnetocaloric effect in the layered room-temperature monoclinic ferromagnet Cr$_{1.38}$Te$_2$. The critical behavior is studied by employing various techniques such as the modified Arrott plot (MAP), the Kouvel-Fisher method (KF), and the critical isothermal analysis (CI) around the Curie temperature ($T_C$) of 316 K. The derived critical exponents are self-consistent and obey the rescaling analysis. The Monte-Carlo simulations reproduce the experimentally obtained critical exponents. However, the derived critical exponents do not suggest any single universality class of the magnetic interactions. On the other hand, the renormalization group (RG) theory suggests 3D-Ising type long-range exchange interactions [$J(r)$], decaying with distance ($r$) as $J (r) = r^{-(d+\sigma)}= r^{-4.73}$. Further, magnetocrystalline anisotropy energy density (K$_u$) is found to be temperature dependent. The ground state magnetic easy-axis ($b$-axis) is identified by analyzing the magnetocrystalline anisotropy energy (MAE) using the density functional theory calculations. Maximum entropy change -$\Delta S_{m}^{max}$$\approx$2.51 J/kg-K is found near the $T_C$.