The effect of Mn substitution in LaFe_11.7Si_1.3compound on the magnetic properties and magnetic entropy changes

Abstract

The magnetic properties and magnetic entropy changes of La(Fe1−xMnx)11.7Si1.3 (x = 0–0.03) have been studied. The Curie temperatures TC decrease monotonously with increasing Mn concentration from 188 to 127 K, and the saturation magnetization μS decreases from 23.9 μB/fu to 22.2 μB/fu respectively, as x increases from 0 to 0.03. The maximal magnetic entropy changes |ΔS|, under a magnetic field change of 0–5 T, are 26.0 J kg−1K −1, 25.7 J kg−1K −1, 20.8 J kg−1K −1 and 17.1 J kg−1K −1 for x = 0, 0.01, 0.02 and 0.03, respectively. The appearance of negative slopes in the Arrott plots for all samples confirms the occurrence of a first-order field-induced itinerant-electron metamagnetic (IEM) transition. Furthermore, the full-width at half-maximum (FWHM) of |ΔS| peak, δTFWHM, increases obviously with increasing Mn content, which results in the decrease of the maximum magnetic entropy change.