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

We report upon the excellent magnetocaloric properties of Gd53Al24Co20Zr3 amorphous microwires. In addition to obtaining the large magnetic entropy change (-Delta S-M similar to 10.3 J/kg K at T-C similar to 95 K), an extremely large value of refrigerant capacity (RC similar to 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 (similar to 410 J/kg) and Gd5Si2Ge1.9Fe0.1 (similar to 360 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. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4751038]