Reduction of Hysteresis Loss in Itinerant-Electron Metamagnetic Transition of La<SUB>1−<I>z</I></SUB>Ce<I><SUB>z</SUB></I>(Fe<I><SUB>x</SUB></I>Mn<I><SUB>y</SUB></I>Si<SUB>1−<I>x</I>−<I>y</I></SUB>)<SUB>13</SUB> Magnetic Refrigerants at Low Temperatures

Abstract

Since La 0.75 Ce 0.25 (Fe 0.85 Mn 0.03 Si 0.12 ) 13 itinerant-electron metamagnet exhibits large magnetocaloric effects at low temperatures because of the itinerant-electron metamagnetic (IEM) transition, the reduction of hysteresis loss E h estimated from the enclosed area between the ascendant and descendant magnetization has been investigated. We have found that E h associated with the IEM transition of La 0.75 Ce 0.25 (Fe 0.85 Mn 0.03 Si 0.12 ) 13 is remarkably reduced from 78 to 3 J/kg by a slight adjustment of compositions, that is, the increase of the Ce concentration up to z = 0.35 and the decrease of the Fe concentration down to x = 0.84. What is important is that such improvement is achieved without a striking decrease of the isothermal magnetic entropy change ΔS m at low temperatures.