Anisotropic magnetic properties and critical behaviour studies of trigonal Cr5Te8 single crystal

Abstract

Magnetic and magnetocaloric properties of the single crystalline Cr5Te8 have been studied. Temperature dependent dc and ac magnetization of Cr5Te8, upon cooling, reveals a paramagnetic to ferromagnetic transition at ≈ 220 K (TC). Field dependent magnetization in the ordered state at 2 K reveals strong anisotropy with c-axis as the easy axis of magnetization. A weak itinerant behaviour of Cr-spins is also ascertained from the magnetization studies. Magnetocaloric effect in terms of isothermal magnetic entropy change has been estimated to be ≈-2 J/kg·K near TC for a field change of 70 kOe. The magnetic transition at TC is found to be second order. Critical behaviour analysis along the easy axis direction in Cr5Te8 suggests that this system does not belong to a particular universality class. However, the estimated critical exponent values β = 0.363, γ = 1.399 and δ = 4.83 from modified Arrott plots and scaling of magnetocaloric behaviour satisfactorily obeys the scaling hypothesis wherein the experimental isothermal magnetization curves collapse onto two branches of universal curves below and above TC. Our critical behaviour analyses confirm the quasi-2D weak itinerant ferromagnetic short range type interaction in Cr5Te8.