Magnetocaloric effect near room temperature and critical behaviour of Fe doped MnCo0.7Fe0.3Ge

Abstract

We report on the critical magnetic behaviour, universality class and magnetocaloric properties of Mn0.7Fe0.3Co0.7Fe0.3Ge. At room temperature, the alloy is found to crystallize in the hexagonal structure of Ni2In-type. Paramagnetic to ferromagnetic phase transition is found to occur at a Curie temperature of about 298 K. The saturation magnetization value at low temperatures is about 2.79 μB/f.u. Kouvel-Fisher and modified Arrott's Plot methods along with magnetocaloric method are implemented to determine the critical exponents which are found to be self-consistent. The critical exponents suggest short range magnetic interactions with 3D-Heisenberg universality class of the alloy as inferred from the relationJ(r)~1/r5.02. Around the Curie temperature, the maximum change in the magnetic entropy, under the influence of 90 kOe, is about −3.91 J kg−1 K−1.