Magnetic Critical Behaviors in Crystalline Cr₃Te₄

In a 2^nd order magnetic phase transition, correlation length diverges, and thermodynamic quantities exhibit power-law dependencies as a function of the distance away from the phase transition. The extracted powers are known as critical exponents, and their magnitudes shed light on the nature of the magnetic phase transition and possible applications of these materials. Monoclinic Cr₃Te₄ is a promising candidate for room-temperature spintronics and magnetocaloric applications. Here we investigate the critical behaviors around the paramagnetic-to-ferromagnetic phase transition of Cr₃Te₄ crystals. Synchrotron XRD and Laue diffraction are used to determine its phase and crystallographic axes, respectively. We estimate critical exponents (β = 0.3827, γ = 1.2119, and δ = 4.1416) and the Curie temperature T_C ~ 321 K by modified Arrott plot, Kouvel-Fisher plot, and critical isotherm analysis. Our analysis suggests that critical behaviors in this material cannot be described by any known theoretical model. Presence of multiple interactions in this system may well explain this discrepancy of critical exponent values between our estimation and known theoretical models.