Strain-induced effects on the physical properties of rare-earth magnetic oxides RMO3 (R= La, Pr; M = Fe, Mn); via first principles

Abstract

The impact of uniaxial strain on the structure, electronic, magnetic, and elastic characteristic of rare-earth transition metal oxides RMO₃ (R= La, Pr; M = Fe, Mn) are investigated for potential applications in magnetic storage devices, sensors, photovoltaics, and electronic devices using first-principles based density functional theory calculations, incorporating the Hubbard parameter U. These materials are stable in orthorhombic crystal symmetry (space group Pnma No. 62) and possesses spontaneous MO₆ octahedral distortion, which causes stability in the crystal lattice and is responsible to arise cooperative Jahn-Teller (JT) distortions. There is a strong influence of strain on structure parameters such as lattice constants, bond lengths and Q₂/Q₃ vibrational modes. This influence provides a knob for tuning the physical properties of these materials, which is essential for advanced materials engineering in their technological applications. G-type antiferromagnetic (G-AFM) phase was found to have a favorable magnetic ground state and can be tuned with strain, which can enhance the storage capacity of these materials. These materials are direct band and optically active materials with ground state band gap values 2.11, 2.06, 2.01 and 2.03 eV for LaFeO₃, PrFeO₃, LaMnO₃, and PrMnO₃ respectively, the band gap values lies in the visible region of electromagnetic spectrum, enable them for advanced technological applications in transistors, photo-detectors and optoelectronic devices. Further the band gap values can be tuned via strain for desired device applications. The elastic constants calculations reveal that the crystallographic c-axis is more favorable for compressibility as compared to a- and b-axis.