ELECTRONIC STRUCTURE, MAGNETIC, OPTICAL, VIBRATIONAL, AND THERMODYNAMIC PROPERTIES OFBIFE03

• Main Author: Glory Adi Winning Kusu, Ignatio
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/46422
• Institution: Institut Teknologi Bandung

The electronic structure, magnetic, optic, vibrational, and thermodynamical propertis of multiferroic material of BiFe03 has been studied computationally within Density FunctiOnal Theory (DFT). Pseudopotential and Projector Augmented Wave (PA) meth<><!s were employed with the generalized gradient approximation of exchange-correlanon potential from Perdew, Burke, and Ernzerhof (PBE-GGA) which was implemented in the computer code ABlNIT. Hubbard parameter, U as a correction for OFT calculation was needed to obtain the electronic structure accurately. The U parameter was varied from 0 to 4 eV and it was used as a comparison to the experimental result. By analyzing the density of states (DOS), we have information about the transition between the 2p 0 states of the upper valence band to the 3d Fe states of the lower conduction band give an indirect energy gap value of 2.09 eV. The structure parameter and band gap energy of the material are in a good agreement with the experimental result. Antiferromagnetic properties of BiFe03 was observed from the anti­ parallel spin arrangement of two atoms of Fe in the unit cell, with the local magnetic moment of ±4.013 Bohr Magneton. Ferroelectric properties comes from a lone pair of 6s Bi orbital which forms Bi06 distorted octahedra. For the optical properties, the absorption coefficient has been calculated with various value of U parameter under density functional perturbation theory (DFPT). The value of U, which suits the experimental result is 3.091 eV. Phonon dispersion curve has been calculated and the acoustic and optical modes had been observed under DFPT. From the phonon density of states, Helmholtz free energy (F), internal energy (E), entropy (S), and calor capacity (Cv) of BiFe03 has been obtained as a function of temperature.