Thermal stability, magnetic and magnetocaloric properties of Gd₅₅Co₃₅M₁₀ (M = Si, Zr and Nb) melt-spun ribbons

The thermal stability, magnetic and magnetocaloric properties of Gd₅₅Co₃₅M₁₀ (M = Si, Zr and Nb) melts-pun ribbons were studied. The relatively high reduced glass transition temperature (T_x1/T_m > 0.60) and low melting point (T_m) resulted in excellent glass forming ability (GFA). The Curie temperatures (T_C) of melt-spun amorphous ribbons Gd₅₅Co₃₅M₁₀ for M = Si, Zr and Nb were 166, 148 and 173 K, respectively. For a magnetic field change of 2 T, the values of maximum magnetic entropy change (−ΔS_M)^max for Gd₅₅Co₃₅Si₁₀, Gd₅₅Co₃₅Zr₁₀ and Gd₅₅Co₃₅Nb₁₀ were found to be 2.86, 4.28 and 4.05 J kg⁻¹K⁻¹, while the refrigeration capacity (RC) values were 154, 274 and 174 J kg^–1, respectively. The RC_FWHM values of amorphous alloys Gd₅₅Co₃₅M₁₀ (M = Si, Zr and Nb) are comparable to or larger than that of LaFe_11.6Si_1.4 crystalline alloy. Large values of (−ΔS_M)^max and RC along with good thermal stability make Gd₅₅Co₃₅M₁₀ (M = Si, Zr and Nb) amorphous alloys be potential materials for magnetic cooling operating in a wide temperature range from 150 to 175 K, e.g., as part of a gas liquefaction process.