Magnetocaloric and magnetoresistance properties in Co-based (Co0.402Fe0.201Ni0.067B0.227Si0.053Nb0.05)(100-x)Cu-x (x=0-1) glassy alloys

Abstract

The magnetocaloric and magnetoresistance properties of amorphous Co-based (Co0.402Fe0.201Ni0.067B0.227Si0.053Nb0.05)(100-x)Cu-x (x=0, 0.5, 0.75 and 1) ribbons were investigated. Cu additions changed the crystallisation temperature (T-x) and the Curie temperature (T-C). The saturation magnetisation (M-s) and coercivity (H-c) for alloys were in the range of 65.51-38.49 emu/g and 1.99-6.84 A/m, respectively. Under an applied magnetic field change of 2.2 T, the (-S-M)(max) for (Co0.402Fe0.201Ni0.067B0.227Si0.053Nb0.05)(100-x)Cu-x with x=0, 0.5, 0.75 and 1 are 0.77, 0.71, 0.89 and 0.67 Jkg(-1)K(-1), respectively. The values of refrigeration capacity (RC) for the as-spun glassy alloys are comparable with those of previously studied Fe-based metallic glasses such as Fe80B10Zr9Cu1, (Fe0.76B0.24)(96)Nb-4 and Fe82Ni2Zr6B10. In addition, the maximum magnetoresistance (MR) values for (Co0.402Fe0.201Ni0.067B0.227Si0.053Nb0.05)(100-x)Cu-x with x=0, 0.5, 0.75 and 1 are found to be 110, 38, 23 and 1% around the Curie temperatures under an applied magnetic field change of 1 T, respectively. With good RC, negligible hysteresis due to very low coercivity values and large magnetoresistance, these Co-based amorphous alloys can be used as the high temperature magnetic refrigerants and multifunctional applications working in the temperature range of 450-600K.