Effects of Exchange, Anisotropic, and External Field Couplings on a Nanoscale Spin-2 and Spin-3/2 System: A Thermomagnetic Analysis

In this research, an analysis of the thermomagnetic properties of a nanoscale spin-2 and spin-3/2 system is conducted. This system is modeled with as a quasi-spherical Ising-type nanoparticle with a diameter of 2 nm, in which atoms with spin-2 and spin-3/2 configured in body-centered cubic (BCC) lattices interact within their relevant nanostructures. To determine the thermomagnetic behaviors of the nanoparticle, numerical simulations using Monte Carlo techniques and thermal bath class algorithms are performed. The results exhibit the effects of exchange couplings (J1,J2′), magnetocrystalline anisotropies (D3/2′,D2′), and external magnetic fields (h′) on the finite-temperature phase diagrams of magnetization (MT), magnetic susceptibility (χT), and thermal energy (kBT′). The influences of the exchange, anisotropic, and external field parameters are clearly reflected in the compensation, hysteretic, and pseudocritical phenomena presented by the quasi-spherical nanoparticle. When the parameter reflecting ferromagnetic second-neighbor exchanges in the nanosphere (J2′) increases, for a given value of the external magnetic field, the compensation (Tcomp) and pseudocritical (Tpc) temperatures increase. Similarly, in the ranges 0<J2′⩽4.5 and −15⩽h′⩽15 at a specific temperature, an increase in J2′ results in the appearance of exchange anisotropies (exchange bias) and and increased hysteresis loop areas in the nanomodel.