Magnetocaloric properties of alloys

The Curie temperature of the Gd6(Mn1−xFex)23 ( x ≤ 0.2 ) ferrimagnets evolves with the Fe content from T C = 489 K for x = 0.0 down to T C = 176 K for x = 0.2 . The Fe for Mn substitution also yields a decrease of the maximal magnetization recorded at 5 K in a 9 T magnetic field ( 54.7 μ B / f.u. and 42.0 μ B / f.u. for x = 0.0 and x = 0.2 , respectively). These alloys present an anomalous magnetocaloric effect. The magnetocaloric response extends over a broad temperature interval from T C down to the lowest temperatures, with two − Δ S M maxima of moderate magnitude at T C and near 100 K. This yields a large cooling capacity q ∼ 3.3 J/cm 3 for μ 0 Δ H = 5 T .