First principles and mean fieldstudy on the magnetocaloric effectofYFe3 and HoFe3 compounds

In this work, the magnetothermal characteristics and magnetocaloric effect in YFe3 and HoFe3compounds are calculated as function of temperature and magnetic field. These properties wereinvestigated using the two‑sublattice mean field model and the first‑principles DFT calculation usingthe WIEN2k code. The two‑sublattice model of the mean‑field theory was used to calculate thetemperature and field‑dependences of magnetization, magnetic heat capacity, magnetic entropy, andthe isothermal change in entropy ∆Sm. We used the WIEN2k code to determine the elastic constantsand, subsequently, the bulk and shear moduli, the Debye temperature, and the density‑of‑statesat Ef. According to the Hill prediction, YFe3 has bulk and shear moduli of roughly 99.3 and 101.2 GParespectively. The Debye temperature is ≈ 500 K, and the average sound speed is ≈ 4167 m/s. In fieldsup to 60 kOe and at temperatures up to and above the Curie point for both substances, the trapezoidalmethod was used to determine ∆Sm. For instance, the highest ∆Sm values for YFe3 and HoFe3 in 30kOe are approximately 0.8 and 0.12 J/mol. K, respectively. For theY and Ho systems, respectively,the adiabatic temperature change in a 3 T field decreases at a rate of around 1.3 and 0.4 K/T. Theferro (or ferrimagnetic) to paramagnetic phase change in these two compounds, as indicated by thetemperature and field dependences of the magnetothermal and magnetocaloric properties, ∆Smand ∆Tad, is a second‑order phase transition. The Arrott plots and the universal curve for YFe3 werealso calculated and their features give an additional support to the second order nature of the phasetransition.T