Thermoelastic properties of BiFeO3 under different pressure conditions

Abstract

Bismuth ferrite (BiFeO₃) is a ubiquitously researched room-temperature multiferroic perovskite, which is simultaneously a ferroelectric, antiferromagnetic and ferro elastic ordering. Its pressure stability is of specific concern to possible use in memory devices, spintronics, and energy conversion technologies. In this paper, thermoelastic and pressure-dependent thermodynamic properties of BiFeO₃ are systematically studied by means of a combination of first-principles data and thermodynamic modeling using multiple equations of state (EOS) to Shanker, Poirier Tarantola, Bardeen and Srivastava-Pandey formulations, to provide a strong cross-validation of results. The development of pressure of bulk modulus, shear modulus has been investigated to distinguish anisotropic responses of elasticity and mechanical stability measures. Computed quantities like Gruneisen parameter and Lattice constant were solved at different compression, noting the interplay between lattice dynamics and elastic stiffness. Findings indicate that elastic moduli increase continuously with pressure, which means that the structural rhombohedral phase is more incompressible and stable until a critical pressure is reached at which new structural instabilities may occur. Gruneisen parameter decreases with pressure, which indicates a decrease in anharmonicity of lattice vibration. The results of these studies can be of great use in the elastic thermodynamic interaction of BiFeO₃ at extreme temperatures.

Key words: Isothermal EOS, Bulk Modulus, Lattice Constant, Gruneisen Parameter.