Magnetocaloric properties of a wire composite of La (Fe,Mn,Si)13-H alloy powders in a Gd cylindrical tube

Abstract

The enhancement of magnetocaloric effect (MCE) and the extension of effective magnetic refrigeration temperature region near room temperature are critical requirements for highly efficient and environment friendly cooling technologies. The large isothermal entropy change of the first-order phase transition material and broader temperature range of the second-order phase transition material are combined into the composite form of La(Fe,Mn,Si)13-H and Gd with their transition temperatures close to room temperature. In this work, wire composites were fabricated using the La (Fe,Mn,Si)13-H powders filled inside the Gd tube. The magnetocaloric properties of the wire composite are convoluted from individual constituents. The dual transitions temperature were observed at 287 K and 292 K. The isothermal entropy change response of the wire composite can be obtained by using the simulation with the combined weight of the Gd tube and La (Fe,Mn,Si)13-H powders. The maximum isothermal entropy change (−ΔSiso) at μoH= 5 T calculated from isothermal magnetization measurements are 8.7 for Gd tube, 16.9 for La(Fe,Mn,Si)13-H powders, and 10.2 J/kg•K for a wire composite. The magnetocaloric properties including the order of phase transition of the wire composite are close to second-order type due to the higher weight fraction of Gd tube.