Magnetic, Magnetocaloric, and Critical Properties of Fe84-xCr2+xB2Co2Zr10 Melt-Spun Ribbons

Magnetic properties, magnetocaloric effect, and critical behavior of Fe84-xCr2+xB2Co2Zr10 (x = 1, 2, 3, 4, 5, and 6) rapidly quenched alloy ribbons prepared by melt-spinning method have been investigated. X-ray diffraction analysis shows that the ribbons are almost amorphous. All the ribbons exhibit soft magnetic behavior with a low coercivity, Hc < 20 Oe. The magnetic phase transition temperature of the alloy can be adjusted in the room temperature region by appropriate Cr concentrations. With increasing Cr concentration, Curie temperature (TC) of the alloys is reduced from 330 K (for x = 1) to 290 K (for x = 6). The quite high maximum magnetic entropy change, |ΔSm|max > 0.8 J.kg−1.K−1 (under a magnetic field change of 12 kOe), and the wide working temperature range, δT > 90 K, around room temperature, have been achieved on these alloy ribbons. The obtained results reveal that Fe84-xCr2+xB2Co2Zr10 alloys are potential candidates for the magnetic refrigerants at room temperature region. Using the Arrott-Noakes method, critical analyses around the ferromagnetic-paramagnetic phase transition elucidated the magnetic orders in the alloys. The critical parameters determined for Fe84-xCr2+xB2Co2Zr10 ribbons are close to those of the mean-field theory applied for the long-range ferromagnetic orders.