Magnetic and magnetocaloric properties of Ho$_{1-x}$Y$_{x}$(Co$_{0.84}$Fe$_{0.16}$)$_{2}$ compounds

Сrystal structure, temperature and field dependences of magnetization, high-field susceptibility, and magnetocaloric effect (MCE) of Ho$_{1-x}$Y$_{x}$(Co$_{0.84}$Fe$_{0.16}$)$_{2}$ polycrystalline compounds ($x$ = 0 – 1) in magnetic fields up to 90 kOe in a temperature range of 5 – 400 K are investigated. An analysis of temperature dependences of magnetization $(\sigma)$ showed that, depending on the yttrium content $(x)$, up to three magnetic phase transitions can be simultaneously present in the studied samples: spin-reorientation $(T_\mathrm{sr})$, magnetic compensation point $(T_\mathrm{comp})$, and Curie temperature $(T_C)$. The temperature dependence of the high-field susceptibility $(\chi_{hf})$ of all samples with $x<1$ has an extremum in the vicinity of 100 K, where a significant MCE is observed, associated with a sharp change in the magnetization of the rare-earth sublattice. The temperature dependences of the magnetic entropy change $(\Delta S_m)$ and the adiabatic temperature change $(\Delta T_{ad})$ have a complex shape and reflect all the above-mentioned magnetic phase transitions and four types of magnetic structures observed at different $x$.