Abstract
<jats:p> This article study investigates the magnetic and magnetocaloric properties of MnAs(P) pnictide compounds using first-principles calculations. In the MnAs <jats:sub>0.97</jats:sub> P <jats:sub>0.03</jats:sub> solid solution, a significant decrease in magnetization was observed, corresponding to a transition from ferromagnetic to paramagnetic ordering. The magnetostructural phase transition responsible for this behavior induces a noticeable magnetocaloric effect near the critical temperature. To analyze these phenomena, the local density approximation with gradient corrections (LDA+GGA) was employed. The interatomic exchange integrals were evaluated by differentiating the total energy functional with respect to spin-pair deviations from equilibrium. The results reveal that increasing phosphorus concentration enhances the magnetic anisotropy within structural blocks, necessitating stronger external magnetic fields to achieve complete ferromagnetic alignment. These findings contribute to a deeper understanding of tunable magnetocaloric materials for solid-state refrigeration and magnetic energy conversion app. </jats:p>