Excellent magnetocaloric properties of melt-extracted Gd-based amorphous microwires

Abstract

We report upon the excellent magnetocaloric properties of Gd53Al24Co20Zr3 amorphous microwires. In addition to obtaining the large magnetic entropy change (-DSM rv 10.3 J/kg K at TC rv 95 K), an extremely large value of refrigerant capacity (RC rv 733.4 J/kg) has been achieved for a field change of 5 T in an array of forty microwires arranged in parallel. This value of RC is about 79% and 103% larger than those of Gd (rv410 J/kg) and Gd5Si2Ge1.9Fe0.1 (rv360 J/kg) regardless of their magnetic ordering temperatures. The design and fabrication of a magnetic bed made of these parallel-arranged microwires would thus be a very promising approach for active magnetic refrigeration for nitrogen liquefaction. Since these microwires can easily be assembled as laminate structures, they have potential applications as a cooling device for micro electro mechanical systems and nano electro mechanical systems.