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Spintronic functionalities in multiferroic BiFeO3
Marin Alexe
Department of Physics, University of Warwick,
Coventry CV 4 7AL, United Kingdom
*e-mail: m.alexe@warwick.ac.uk
In the field of multiferroics (MF) several systems have shown coexistence of electric and magnetic order,
some of them with coupling between these order parameters. However, direct evidences of spintronic
functionalities in presence of magnetoelectric coupling are still not systematically reported. Ferroic domain
walls (DWs), which are intrinsically two dimensional nano-objects, are usually showing different
functionalities as the host material. Moreover, they can be created, annihilated, injected, or simply moved,
representing in this way a totally new playground for adaptive functional electronics. Here we show a novel
type of magnetoelectric coupling at the domain walls (DWs) in the multiferroic material BiFeO3 (BFO).
FE domain walls (DWs) in the multiferroic material BFO are not only conductive, but are also showing
spin-dependent transport. We will show the electronic transport across the domain walls in BFO is
modulated by an external applied magnetic field, resembling the anisotropic magnetoresistance (AMR) in
archetypical metallic ferromagnets. We will focus on the occurrence of AMR at the ferroelectric domain
walls of BFO in simple typical capacitor geometry, showing that BFO conductive domain walls display
hysteretical AMR. This effect results from the ferroelectric nature of domain walls magnetically coupled to
the antiferromagnetic domains of BFO. [1]
Independently, the magnetic nature of the ferroelectric domain walls in BFO has been revealed by high
resolution transmission electron microscopy. We will show also the FM-FE coupling at atomic level
domain walls in BFO single crystals at by aberration-corrected transmission electron microscopy in which
all atoms including oxygen are imaged directly.
[1] J. H. Lee, et al. Adv. Mat. 26, 7078 (2014).
[2] C.-L. Jia, et a. Acta Materialia 82, 356 (2015).
Curriculum(Vitae(
Professor Marin Alexe has been recently appointed as Chair of Functional Materials at the
University of Warwick after spending about 18 year at the Max Planck Institute of Microstructure
Physics-Halle. His research interest is physics and engineering of complex oxide thins films for
information technology and integration of functional materials for oxide electronics. He has
published more than 280 papers and 2 books and has an h-index of 41. In the last five years he
has given more than 30 invited talks and lectures at international meeting and conferences. He
was recently awarded the Wolfson Research Merit Award of the Royal Society.