Effect of Fe substitution on magnetocaloric effect in borocarbide superconductor Dy(Ni1-xFex)2B2C

Abstract

Abstract The magnetic properties and magnetocaloric effect (MCE) in antiferromagnetic superconductor Dy(Ni1- x Fe x )2B2C ( x = 0, 0.1, and 0.2) has been studied. The magnetic transition temperature T M as well as the temperature at the maximum of magnetic entropy change (-Δ S M max ) slightly shift to low temperature with increasing x . An inverse MCE was observed, which is attributed to the nature of antiferromagnetic state under low magnetic field and at low temperatures for the present Dy(Ni1- x Fe x )2B2C compounds. A normal large MCE was observed under higher magnetic field changes, which is related to a field-induced first order meatmagnetic transition from antiferromagnetic to ferromagnetic state. Under a magnetic field change of 7 T, the values of -ΔSM max reach 22.1, 16.6, and 14.8 J Kg -1 K -1 for x = 0, 0.1, and 0.2, respectively. The corresponding values of relative cooling power are 464, 332 and 295 J/kg. The observed large magnetic entropy is related to a field-induced first order metamagnetic transition from antiferromagnetic to ferromagnetic state.