Modeling of Magnetic, Magnetocaloric Properties and Dielectrical Characterization of (La_0.75Nd_0.25)_2/3(Ca_0.8Sr_0.2)_1/3MnO₃ Manganite Oxide

In the present work, we aim to analyze the magnetocaloric and electrical properties of (La_0.75Nd_0.25)_2/3(Ca_0.8Sr_0.2)_1/3MnO₃ manganite prepared by solid-state method at high temperature. The experimental results of the magnetization show that the (La_0.75Nd_0.25)_2/3(Ca_0.8Sr_0.2)_1/3MnO₃ compound exhibits a paramagnetic–ferromagnetic transition at T_C = 240 K. In addition to the experimental study, theoretical approaches are adopted to investigate the magnetocaloric behavior of this sample. The important parameters such as maximum entropy change, full width at half maximum (δT_FWHM) and relative cooling power are explained qualitatively. The electrical properties of the studied sample have been investigated by using a complex impedance spectroscopy technique. These electrical measurements reveal that (La_0.75Nd_0.25)_2/3(Ca_0.8Sr_0.2)_1/3MnO₃ sample exhibits a metallic behavior at low temperature and insulator one at high temperature. The temperature (T_MI) of the metal–insulator transition is found to be about 240 K. The effects of frequency, temperature and composition on permittivity ε′, ε″ and dielectric loss (tanδ) have been also discussed in terms of hopping of charge carriers between Mn³⁺ and Mn⁴⁺ ions.