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

摘要

We report upon the excellent magnetocaloric properties of Gd_(52)Al_(2)24Co_(20)Zr_3 amorphous microwires. In addition to obtaining the large magnetic entropy change (-ΔS_M～ 10.3 J/kg K at T_C～95K), an extremely large value of refrigerant capacity (RC～ 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 (～410J/kg) and Gd_5Si_2Ge_(1.9)Fe_(0.1) (～360J/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.