Magnetism and magnetocaloric effect in amorphous ferrimagnetic systems: Application to the Gd[formula omitted]Fe[formula omitted]Al[formula omitted] series.

• Hamiltonian of interacting spins calculated by the Handrich-Kobe approximation. • Amorphous systems with ferrimagnetism and high caloric potentials. • Magnetism, direct and inverse magnetocaloric effect, and magnetic refrigeration. In this work we will investigate the magnetic and magnetocaloric properties in the amorphous alloys formed by the Gd 55 Fe x Al 45 − x series. From an experimental point of view, it has been reported that these systems have high values for refrigerant capacity, and interesting magnetocaloric properties associated with the ferrimagnetic order. We propose a theoretical model described by two coupled magnetic sublattices of localized spins in the presence of an applied magnetic field based on Handrich's approximation to study these systems. Through this model, we calculate the magnetization and the isothermal entropy change as functions of the temperature under the applied magnetic field change. We will try to understand the role of substitution of Fe for Al in the characterization of magnetism and the magnetocaloric effect of these systems. In addition, the study is important to understand the physical mechanisms involved in the ferrimagnetic transitions of amorphous alloys. [ABSTRACT FROM AUTHOR]