Stability and scaling behavior of the spin cycloid in BiFeO3 thin films
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Date
2018-01-30
Journal Title
Journal ISSN
Volume Title
Publisher
Australian Institute of Physics
Abstract
Multiferroic materials demonstrate excellent potential for next-generation multifunctional
devices, as they exhibit coexisting ferroelectric and magnetic orders. Bismuth ferrite (BiFeO3)
is a rare exemption where both order parameters exist far beyond room temperature, making it
the ideal candidate for technological applications. To realize magnonic devices, a robust longrange
spin cycloid with well-known direction is desired, since it is a prerequisite for the
magnetoelectric coupling. Despite extensive investigation, the stabilization of a large-scale
uniform spin cycloid in nanoscale (<300 nm) thin BiFeO3 films has not been accomplished.
Using neutron diffraction we were able to demonstrate cycloidal spin order in 100 nm BiFeO3
thin films which became stable through the careful choice of crystallographic orientation and
control of the electrostatic and strain boundary conditions during growth [1]. Furthermore,
Co-doping, which has demonstrated to further stabilize the spin cycloid, did allow us to obtain
spin cycloid order in films of just 50 nm thickness, i.e. films thinner than the cycloidal length
of about 64 nm. Interestingly, in thin films the propagation direction of the spin cycloid has
changed and shows a peculiar scaling behavior for thinnest films. We were able to support
these observations by Monte Carlo theory based on a first-principles effective Hamiltonian
method. Our results therefore offer new avenues for fundamental research and technical
applications that exploit the spin cycloid in spintronic or magnonic devices.
Description
Keywords
Stability, Scaling, Spin, Thin films, Bismuth, Iron, Ferroelectric materials, Ambient temperature
Citation
Burns, S. R., Sando, D., Bertinshaw, J., Russell, L., Xu, X., Maran, R., Callori, S. J., Ramesh, V., Cheung, J., Danilkin, S. A., Deng, G., Lee, W. T., Bellaiche, L., Seidel, J., Valanoor, N., & Clemens, U., (2018). Stability and scaling behavior of the spin cycloid in BiFeO3 thin films. Paper presented to the 42nd Annual Condensed Matter and Materials Meeting Charles Sturt University, Wagga Wagga, NSW 30th January – 2nd February, 2018. (pp. 27). Retrieved from: https://physics.org.au/wp-content/uploads/cmm/2018/Wagga_2018_Conference_Handbook.pdf