Roy, Amritendu and Mukherjee, Somdutta and Sarkar, Surajit and Auluck, Sushil and Prasad, Rajendra and Gupta, Rajeev and Garg, Ashish (2012) Effects of site disorder, off-stoichiometry and epitaxial strain on the optical properties of magnetoelectric gallium ferrite. Journal of Physics: Condensed Matter, 24 (43). pp. 435501-435510. ISSN 0953-8984

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Abstract

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 GaFeO3 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 GaFeO3 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.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/s IOP Publishing.
Subjects:	Applied Physics/Condensed Matter
Divisions:	UNSPECIFIED
Depositing User:	Users 27 not found.
Date Deposited:	20 Feb 2020 11:40
Last Modified:	20 Feb 2020 11:40
URI:	http://npl.csircentral.net/id/eprint/3609

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