Field dependence of magnetic entropy change: Whence comes an intercept?

Abstract The magnetic field-induced entropy change in a ferromagnet undergoing a second-order phase transition at the Curie point is maximum near that point. The maximum magnetic entropy change, ( - Δ S ) max , is demonstrated to contain, besides the usual term in H 2 / 3 , a small negative term independent of H . Spatial inhomogeneity of real ferromagnetic materials is shown to be the origin of the off-set term, whose magnitude proves proportional to the width of the distribution of local Curie points.