Effect of Fe substitution on magnetocaloric effect in metamagnetic boron-carbide ErNi2−xFexB2C compounds

The magnetic properties and magnetocaloric effect (MCE) in ErNi2−xFexB2C have been studied. Substitution of Fe for Ni lowered the magnetic transition temperature TM, and reduced the magnetic hysteresis of ErNi2B2C. An inverse MCE was observed under low magnetic field and at low temperatures, which is attributed to the nature of antiferromagnetic state for the present ErNi2−xFexB2C compounds. A normal MCE was observed under higher magnetic field changes, which is related to a field-induced first order metamagnetic transition from antiferromagnetic to ferromagnetic state. The maximum values of magnetic entropy change −ΔSMmax are 14.5, 12.7, and 10.6 J/kg K with a magnetic field change of 0-70 kOe for x = 0, 0.1, and 0.2 in ErNi2−xFexB2C, respectively.