2012/10/01 by Amritendu Roy, Somdutta Mukherjee, Surajit Sarkar +4 · 15 citations
Materials Science · Physics and Astronomy · #Band gap #Dielectric #Electronic band structure #Epitaxy #Ferrite (magnet) #Gallium #Ground state #Heusler alloys: electronic and magnetic properties #Magnetic Properties and Synthesis of Ferrites #Multiferroics and related materials #Thin film #cond-mat.mtrl-sci
paper · pdf · doi:10.1088/0953-8984/24/43/435501
published in Journal of Physics Condensed Matter 24(43), 435501 (IOP Publishing) · 18 Pages, 6 figures
arxiv created 2012/10/01 · openalex publication_date 2012/10/03 · arxiv updated 2013/08/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present a combined experimental-theoretical study demonstrating the role of site disorder, off-stoichiometry and strain on the optical properties of magnetoelectric gallium ferrite. Optical properties (bandgap, refractive indices and dielectric constants) were experimentally obtained by performing ellipsometric studies over the energy range 0.8-4.2 eV on pulsed laser deposited epitaxial thin films of stoichiometric gallium ferrite with b-axis orientation and the data were compared with theoretical results. Calculations on the ground state structure show that the optical activity in GaFeO(3) arises primarily from O 2p-Fe 3d transitions. Further, inclusion of site disorder and epitaxial strain in the ground state structure significantly improves the agreement between the theory and the room temperature experimental data substantiating the presence of site disorder in the experimentally derived strained GaFeO(3) films at room temperature. We attribute the modification of the ground state optical behavior upon inclusion of site disorder to the corresponding changes in the electronic band structure, especially in Fe 3d states leading to a lowered bandgap of the material.