Magnetic and magnetocaloric properties of amorphous Y_3Fe_5O_(12) compound

摘要

We report a theoretical model formed by two coupled magnetic sublattices of localized spins in the presence of an applied magnetic field to investigate the magnetic characteristics and magnetocaloric properties of amorphous yttrium iron garnet. The magnetic state equation is based on Handrich-Kobe's theory, where the amorphization is taken into account by introducing fluctuations in the exchange parameters. Experimental results report that Y_3Fe_5O_(12) presents a structural phase transition from crystalline to amorphous caused by a variation of external pressure. This phase transition on Y_3Fe_5O_(12) leads to interesting results in the magnetic properties and magnetocaloric quantities.