Critical behavior, magnetic phase diagram, and magnetic entropy change of MnSb2Te4

The magnetic properties of single-crystal MnSb₂Te₄ were thoroughly investigated. The $M(T)$ curves exhibit anisotropic magnetic behaviors with the c axis as the easy axis in low temperature, while Curie-Weiss fitting curves show an isotropic behavior at high temperature. The evaluated Rhodes-Wohlfarth ratio of 2.25 (2.22) for $H//ab$ $(H//c)$ demonstrates an itinerant high-field ferromagnetic state. Critical exponents β=0.441(9) with TC=19.4(1) K and γ=1.108(13) with TC=19.3(1) K are acquired by the modified Arrott plots, whereas δ=3.52(1) is achieved by a critical isotherm analysis at TC=19.4 K, exhibiting three-dimensional critical behavior and complex magnetic interaction. A detailed H-T phase diagram containing antiferromagnetic, canted antiferromagnetic, and ferromagnetic states is constructed, where two triple points (~310 Oe at 19.4 K and ~1970 Oe at 19.4 K) are achieved. Additionally, the magnetic entropy change ΔSM is evaluated with -ΔSMᵐᵃˣ reaching 2.20 J kg^-10.16em0exK^-1 in the $ab$ plane and 2.20 J kg^-10.16em0exK^-1 along the c axis at $H=70$ kOe. The rotating magnetic entropy change -ΔSMR(T,H) is ~0 J kg^-10.16em0exK^-1 at $T>$ 39 K, displaying a nearly isotropic behavior well above TC, consistent with the above Curie-Weiss fitting; and -ΔSMR is less than 0.24 J kg^-10.16em0exK^-1 at low temperature, demonstrating weak anisotropy.