Study on the Magnetocaloric Effect of Room Temperature Magnetic Refrigerant Material LaPr(FeCo)Si and the Effect Arising from Co Doping on Its Curie Temperature.

The arc-melting method was adopted to prepare the compound LaPr(FeCo)Si ( = 0, 0.02, 0.04, 0.06, 0.08), and the magnetocaloric effect of the compound was investigated. As indicated by the powder X-ray diffraction (XRD) results, after receiving 7-day high temperature annealing at 1373 K, all the compounds formed a single-phase cubic NaZn crystal structure. As indicated by the magnetic measurement, the most significant magnetic entropy change |∆()| of the sample decreased from 28.92 J/kg·K to 4.22 J/kg·K with the increase of the Co content under the 0-1.5 T magnetic field, while the Curie temperature increased from 185 K to the room temperature 296 K, which indicated that this series of alloys are the room temperature magnetic refrigerant material with practical value. By using the ferromagnetic Curie temperature theory and analyzing the effect of Co doping on the exchange integral of these alloys, the mechanism that the Curie temperature of LaPr(FeCo)Si and LaCe(FeCo)Si increased with the increase in the Co content was reasonably explained. Accordingly, this paper can provide a theoretical reference for subsequent studies.