Magnetocrystalline Anisotropy and Magnetocaloric Effect Studies on the Room-temperature 2D Ferromagnetic Cr$_4$Te$_5$

TL;DR

This study investigates the magnetic anisotropy and magnetocaloric properties of 2D ferromagnetic Cr$_4$Te$_5$ crystals at room temperature, revealing critical behavior, anisotropy variation with temperature, and confirming a second order magnetic transition.

Contribution

It provides detailed critical exponents, magnetocrystalline anisotropy, and magnetocaloric effect data for Cr$_4$Te$_5$, and identifies the spin-coupling as 3D Heisenberg-type with long-range interactions.

Findings

Critical exponents: β=0.485, γ=1.202, δ=3.52.

Maximum entropy change: 2.77 J/kg-K near T_C.

Long-range exchange interactions decay as r^{-4.71}.

Abstract

We present a thorough study on the magnetoanisotropic properties and magnetocaloric effect in the layered ferromagnetic Cr$_4$Te$_5$ single crystals by performing the critical behaviour analysis of magnetization isotherms. The critical exponents $\beta$=0.485(3), $\gamma$=1.202(5), and $\delta$=3.52(3) with a Curie temperature of $T_C \approx 340.73(4)$ K are determined by the modified Arrott plots. We observe a large magnetocrystalline anisotropy K$_u$=330 kJ/$m^3$ at 3 K which gradually decreases with increasing temperature. Maximum entropy change -$\Delta S_{M}^{max}$ and the relative cooling power (RCP) are found to be 2.77 $J/kg-K$ and 88.29 $J/kg$, respectively near $T_C$ when the magnetic field applied parallel to $\it{ab}$-plane. Rescaled -$\Delta S_M (T, H)$ data measured at various temperatures and fields collapse into a single universal curve, confirming the second order magnetic transition in this system. Following the renormalization group theory analysis, we find that the spin-coupling is of 3D Heisenberg-type, $\{d:n\}=\{3:3\}$, with long-range exchange interactions decaying as $J (r) = r^{-(d+\sigma)}= r^{-4.71}$.