Magnetic and magneto-thermal properties of ferrimagnetic alloys (Er1-xYx)(Co0.84Fe0.16)2and their dependence on the orientations of resultant and sublattice magnetizations

In this paper structure, magnetic and magneto-thermal properties: magnetic entropy change (ΔS_m) and refrigeration capacity (q) of Er_1-xY_x(Co_0.84Fe_0.16)₂alloys (x= 0, 0.2, 0.4, 0.6, 0.8, 1) in magnetic fields up to 90 kOe in a temperature range of 5-360 K are investigated. An analysis of temperature dependences of magnetization (σ) and high-field susceptibility (χ_hf) showed that in these compounds, three different ferri- and a one ferromagnetic structures are consequently realized. Concentration dependences of magnetic moment at 5 K (μ_f.u.), Curie temperature (T_C), residual magnetization (σ_r) and coercivity (H_c) have been shown to have an extreme at intermediate Y concentration. The character of temperature dependence of magnetic entropy change (ΔS_m(T)) depends on the composition and originates from the type of magnetic structure of the compound and the mutual orientation of R- and 3d- element sublattices magnetization with respect to the resulting one. In compounds withx= 0.6 andx= 0.8 temperature regions with different signs of ΔS_mare observed, reflecting the change of dominating R- or 3d- sublattice in the resulting magnetization.