Suppression of the spin spiral in an antiferromagnetic BiFe 0.5 Mn 0.5 O3 thin film and powder
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Date
2012-02-02
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Publisher
Australian Institute of Physics
Abstract
Since the advent of the spintronics paradigm [1], there has been a resurgence of interest in materials that simultaneously possess magnetic and ferroelectric ordering [2]. Such materials provide the realistic prospect of manipulating magnet elements using electric fields at room temperature. While electric field control has recently been demonstrated using the interfacial coupling between a multiferroic oxide and a metallic thin film [3], there is still a search to find a suitable single phase ferromagnetic multiferroic [4,5]. Previous work reported that a
metastable phase of BiMnO3 was ferromagnetic with a Curie temperature of 99K [5] whereas BiFeO3 . is a canted anti-ferromagnetic below 640K with ferroelectric order [2]. We explored the effect on magnetic structure of including high percentages of Mn into a BiFeO3 host in a La0.2BiFe 0.5 Mn 0.5 O3 compound. Neutron diffraction was performed on an epitaxial nanoscale film using the instrumentation at ANSTO to obtain the magnetic structure at low temperature, and the results were compared with powders and magnetometry data. The neutron data for the film and powders both indicate a single magnetic transition to a highly collinear G-type
antiferromagnetic order where the incommensurate spin spiral present for BiFeO3 appears to be suppressed by the addition of Mn . The Neél temperature is shifted to 225 K. The c/a ratio of the unit cell is found to differ between thin film and the powder suggesting that the epitaxial lattice matching to the SrTiO3 substrate strains the film in the ab plane but preserves the overall unit cell volume leading to a lattice expansion in the c direction and a further reduction in Neel temperature to 130 K. The magnetic properties of the film and powder appear to be dramatically different from the properties of nanoparticles reported for the same compound which showed multiple magnetic transitions to higher temperatures [4].
Description
Keywords
Spin, Antiferroelectric materials, Ferroelectric materials, Bismuth, Iron, Manganese, Thin films, Powders, Coupling, Curie point, Nanoparticles
Citation
Cortie, D. L., Du, Y., Cheng, ZX, Klose, F., & Wang, X. L. (2012). Suppression of the spin spiral in an antiferromagnetic BiFe 0.5 Mn 0.5 O3 thin film and powder. Paper presented to the 36th Annual Condensed Matter and Materials Meeting, Wagga 2012, Charles Sturt University, Wagga Wagga, NSW, 31st January – 3rd February, 2012. Retrieved from: https://physics.org.au/wp-content/uploads/cmm/2012/