Studying multiferroic BiFeO3 and ferromagnetic La0.67Sr0.33MnO3 tunnel junctions with Raman spectroscopy and neutron scattering techniques

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Date
2011-02-02
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Australian Institute of Physics
Abstract
Bismuth Ferrite (BiFeO3 or BFO) is a prominent multiferroic material candidate for industrial implementation as it is among one of the rare cases where ferroelectric polarisation and magnetic order coexist at room temperature [1]. We have investigated its potential in functional thin film heterostructures, where it is possible the interplay between FE and FM at the interface between layers can enable controllable magnetoelectric coupling, allowing for the control of the magnetic polarisation through applied electric fields and vice-versa [2]. Epitaxial (001) BiFeO3 / La0.67Sr0.33MnO3 (LSMO) multiferroic tunnel junctions have been grown by pulsed laser deposition at the University of NSW [3]. These trilayer systems layer: 40nm of LSMO, 10nm of BFO, and 40nm of LSMO on a SrTiO3 substrate, with a RMS roughness of not more than one unit cell. We have found initial experimental evidence of a correlation between the spin polarisation of the FM LSMO layers and the FE polarisation of the BiFeO3 layer through flips in the domain structure through a number of electrical resistance based experimental techniques [3]. We plan to combine results from Raman spectroscopy conducted at the UNSW with polarised neutron reflectometry on PLATYPUS and inelastic neutron scattering on TAIPAN at the Bragg Institute, ANSTO to perform a detailed analysis of: the magnetisation reversal process in the LSMO contact layers, the interplay (exchange bias) between the BFO AFM and LSMO FM parameters, the magnetic depth profile of the heterostructure, in particular the interface regions, and the effect of switching the electric polarisation of the BiFeO3 layer on the domain wall structure, and therefore on the magnetic structure of the entire thin film system.
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Keywords
Bismuth, Ferrite, Ferromagnetic materials, Tunnel junctions, Raman spectroscopy, Scattering, Thin films, Layers, ANSTO, New South Wales
Citation
Bertinshaw, J., Saerbeck, T., Nelson, A., James, M., Nagarajan, V., Klose, F., & Ulrich, C. (2011). Studying multiferroic BiFeO3 and ferromagnetic La0.67Sr0.33MnO3 tunnel junctions with Raman spectroscopy and neutron scattering techniques. Poster presented to the Australian and New Zealand Institutes of Physics 35th Annual Condensed Matter and Materials Meeting, Charles Sturt University, Wagga Wagga, NSW, 2nd - 4th February, 2011. Retrieved from: https://physics.org.au/wp-content/uploads/cmm/2011/