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

Abstract In this paper structure, magnetic and magneto-thermal properties: magnetic entropy change (Δ S m ) and refrigeration capacity ( q ) of Er 1– x Y x (Co 0.84 Fe 0.16 ) 2 alloys ( 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 (Δ S 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 with x = 0.6 and x = 0.8 temperature regions with different signs of Δ S m are observed, reflecting the change of dominating R- or 3d- sublattice in the resulting magnetization.