Carbon-doping effects on the metamagnetic transition and magnetocaloric effect in MnAsCx

Carbon doping effects in MnAs alloys have been investigated. More carbon doping in MnAs alloys leads to lower Curie temperature, larger thermal hysteresis and sharper slope of the dependence of critical field on reduced temperature due to severe lattice distortion. The obtained maximum of magnetic entropy change for a field change of 5 T is about 12.8 Jkg(-1) K(-1) near room temperature, and increases with more doping carbon content to about 22.4 Jkg(-1) K(-1) in MnAsC(0.03) and 13.2 Jkg(-1) K(-1) in MnAsC(0.05). (C) 2010 Elsevier B.V. All rights reserved.