Investigation of the structural, electrical, and dielectric properties of La0.5Sm0.2Sr0.3Mn1-x Cr x O3 for electrical application.

In the present research, polycrystalline samples of La0.5Sm0.2Sr0.3Mn1-x Cr x O3 are prepared using the self-combustion method. Then, we have studied their crystalline structure, and dielectric and electrical properties. The X-ray diffraction study shows that all the samples exhibit a single phase with orthorhombic structure (space group Pnma). The studied samples were also characterized by complex impedance spectroscopy in a wide range of temperatures and frequency. AC conductivity analyses are used to study the transport property of the investigated samples. These analyses indicate that the conduction mechanism is strongly dependent on temperature and frequency. It is also found that the conductivity decreases with Cr concentration. Complex impedance analysis confirms the contributions of grain and grain boundaries in the conduction mechanism. Finally, the impedance spectra, characterized by the appearance of semicircle arcs at different temperatures, were well modeled in terms of equivalent electrical circuits to explain the impedance results.

Study of the structural, electronic, magnetic and magnetocaloric properties of La0.5Ca0.5Mn0.9V0.1O3 sample: first-principles calculation (DFT-MFT).

This paper presents a correlation between experimental and theoretical approaches to study the structural, electronic, magnetic, and magnetocaloric properties of La0.5Ca0.5Mn0.9V0.1O3. The studied compound crystallizes in the Pbnm orthorhombic space group. The calculated DOS using the DFT + U method proves that La0.5Ca0.5Mn0.9V0.1O3 sample exhibits semi-metallic behavior, which is preferred in spintronic applications. The calculated PDOS proves that the high hydration among Mn 3d, V 3d and O 2p at the Fermi energy level is responsible for the FM behavior of La0.5Ca0.5Mn0.9V0.1O3. The magnetic moment has been calculated using DFT results by estimating the valence electron population. The optical properties show high light absorption in the UV region. By using the Bean-Rodbell method, the magnetic phase shows a second-order transition where η = 0.85, and the exchange parameter λ is found to be 1.19 T g-1 emu-1. Based on the mean-field theory, the saturation magnetization (M 0), the Landé factor (g), and the total angular momentum (J) were determined. These parameters were used to simulate magnetization as a function of the magnetic field at different temperatures as well as the variation of the magnetic entropy change ΔS M (T).