Anisotropic magnetocaloric effect in Fe3−x GeTe2

Abstract

Abstract We present a comprehensive study on anisotropic magnetocaloric porperties of the van der Waals weak-itinerant ferromagnet Fe3−x GeTe2 that features gate-tunable room-temperature ferromagnetism in few-layer device. Intrinsic magnetocrystalline anisotropy is observed to be temperature-dependent and most likely favors the long-range magnetic order in thin Fe3−x GeTe2 crsytal. The magnetic entropy change ΔS M also reveals an anisotropic characteristic between H//ab and H//c, which could be well scaled into a universal curve. The peak value $$-\Delta {S}_{M}^{{\max }}$$ −ΔSMmax of 1.20 J kg−1 K−1 and the corresponding adiabatic temperature change ΔT ad of 0.66 K are deduced from heat capacity with out-of-plane field change of 5 T. By fitting of the field-dependent parameters of $$-\Delta {S}_{M}^{{\max }}$$ −ΔSMmax and the relative cooling power RCP, it gives $$-{\rm{\triangle }}{S}_{M}^{{\max }}$$ −∆SMmax ∝ H n with n = 0.603(6) and RCP ∝ H m with m = 1.20(1) when H//c. Given the high and tunable T c , Fe3−x GeTe2 crystals are of interest for fabricating the heterostructure-based spintronics device.