Magnetic properties and magnetocaloric effect in amorphous FeNiCr (SiB) ribbons

Amorphous Fe76-xNixCr4(SiB)(20) (x = 12 and 25) ribbons were prepared using melt spinning technique. Their structural, magnetic and magnetocaloric properties were investigated using X-ray diffraction, vibrating sample magnetometer, and Mossbauer spectrometry. The samples were found to be amorphous. Room Mossbauer measurements ensured the amorphous state of Fe76-xNixCr4(SiB)\(20) ribbons and get further information about the effect of Ni content in the hyperfine parameters. The magnetic transition was analyzed in terms of Landau theory around the transition temperature. The amorphous alloys exhibit a second order transition from ferromagnetic to paramagnetic phase. With increasing Ni concentration, the Curie temperature decreases as well as the maximum entropy change(-Delta S-m(max) ) and relative cooling power (RCP). In addition, a phenomenological model was used to predict reasonably the magnetocaloric parameters.