Iron for nickel substitution effects on magnetic and magnetocaloric properties of melt-spun Gd75(Ni1-xFex)25 alloys

The melt quenched Gd₇₅(Ni_1-xFe_x)₂₅ alloys are found to exhibit a soft ferrimagnetic behavior in the whole concentration range (0 ≤ × ≤ 1). Substitution of Fe for Ni in the Gd₇₅(Ni_1-xFe_x)₂₅ alloys results in a linear growth of the magnetic ordering temperature from 118 K to 244 K; although, an average value of the magnetic moment per transition metal atom, obtained from saturation magnetization measurements, does not change significantly with increasing Fe content. The variations of the Curie temperature and magnetization in Gd₇₅M₂₅-type amorphous alloys (M = Fe, Ni) are discussed bearing in mind a possible noncollinearity of magnetic moments of 3d metal atoms. The maximal values of the isothermal magnetic entropy change (ΔS_m) are observed to exhibit the Fe-poor Gd₇₅(Ni_1-xFe_x)₂₅ alloys. The change in the concentration of 3d-metal of different types in amorphous Gd₇₅M₂₅ alloys with a constant gadolinium content makes it possible to vary both the magnetocaloric effect and the operating temperature range.