Experimental estimation of cooling power of a solid state micro magnetic refrigerator using La(FexSi1−x)13Hy

We demonstrated microscale cooling by a solid state micro magnetic refrigerator (SSMMR). The SSMMR consists of thermally isolated magnetic material (La(Fe_xSi_1-x)₁₃H_y), two thermal switches and a magnetic field switch. Thermal isolation structure and thermal switch were fabricated using MEMS fabrication process. The magnetic field switch were designed and fabricated to change the magnetic flux density between 0 T and 1 T. Under this magnitude of magnetic field modulation, the La(Fe_xSi_1-x)₁₃H_y showed a temperature change of ca. 1 °C. By the refrigeration cycle, about 0.6 °C cooling effect was observed on the thermally isolated cold plate. From these results, the estimated cooling power of the SSMMR was ca. 9 μW.