Magnetocaloric effect and critical behavior in Fe-La-Zr rapidly quenched ribbons

Abstract

Fe90-xLaxZr10 (x = 1 and 2) rapidly quenched ribbons with thickness of about 15 μm were prepared by the melt-spinning method. X-ray diffraction analysis shows that the structure of the ribbons is mostly amorphous. The Curie temperature, TC, of the alloy considerably increased, from ∼262 K for x = 1 to ∼302 K for x = 2, with increasing La-concentration. The maximum magnetic entropy change, |ΔSm|max, of the alloy is about 1.1 J∙kg−1K−1 for a magnetic field change ΔH = 12 kOe. A quite large refrigerant capacity (RC ∼ 74 J∙kg−1 for ΔH = 12 kOe) near the room temperature region is obtained for the alloy. A thorough analysis on critical exponents around the ferromagnetic-paramagnetic phase transition, using the Arrott–Noakes plots and Kouvel–Fisher method, sheds light on the critical magnetic behavior and its association with the magnetocaloric effect in the Fe-La based alloys. Keywords: Magnetocaloric effect, Magnetic refrigerant, Critical parameter, Magnetic entropy change, Melt-spinning method