Experimental study and DFT calculation of the oxygen deficiency effects on structural, magnetic and optical properties of La0.8□0.2MnO3-δ (δ = 0, 0.1 and 0.2) compounds

Abstract

In this work, our main focus is to study the effect of oxygen vacancy on structural, magnetic, and optical properties of La0.8□0.2MnO3-δ (δ = 0, 0.1 and 0.2) manganites. The refinement of X-ray diffraction patterns shows that the samples with δ = 0 and 0.1 crystallize in the rhombohedral phase with R3¯c space group. Also, for δ = 0.2 the refinement has revealed the coexistence of R3¯c rhombohedral and Pnmaorthorhombic phases. The magnetic measurements M (T) shows that our samples have a transition from the ferromagnetic (FM) state to the paramagnetic (PM) state by increasing the temperature. The increase of oxygen deficiency rate causes a spin-glass-like state at low temperature with the presence of Griffiths phase above Curie temperature. Moreover, the hysteresis loop analysis shows an increase in the remanent magnetization and the coercive field when the creation of oxygen deficiency. Also, we find an agreement between experimental results and a theoretical study using ab initio density functional theory (DFT) based on correct Spin polarized Generalized Gradient Approximation SGGA + U. The results of the optical properties calculation revealed that our compounds could produce high absorption in the ultraviolet range.