The effect of Sr doping on the electronic structure and electromagnetic properties of LaCo0.9Fe0.1O3 perovskites

Abstract

In this work, an electronic structure study of La_1−xSr_xCo_0.9Fe_0.1O₃ (LSCFO) perovskites was performed. The LSCFO perovskites were fabricated via a simple sol–gel method and subsequent calcination by modulating the molar ratio of La³⁺/Sr²⁺. It was found that Sr doping could destroy the crystal structure of LaCo_0.9Fe_0.1O₃ (LCFO), resulting in lattice expansion. The enhancement in the magnetic performance was chiefly derived from the crystal structure defects. In addition, the valence state transition of Co³⁺ to Co²⁺ led to the formation of oxygen vacancies due to partial substitution of La³⁺ by Sr²⁺. Then,La_1−xSr_xCo_0.9Fe_0.1O₃ (x = 0.3) could achieve a minimum reflection loss (RL) of −45.1 dB at 4.32 GHz and an effective absorption bandwidth (EAB) of 3.1 GHz with a matching thickness of 1.7 mm. More importantly, the density functional theory (DFT) and first principles calculations were employed to calculate the electronic structure of LSCFO perovskites, revealing that the magnetic and polarization performances were significantly enhanced with the increasing concentration of Sr doping. These results drive the development of LSCFO perovskites with potential applications in high-efficiency microwave absorbents.