Domain switching in multiferroic bismuth ferrite nanoislands. 1 A.Morelli*1, R. McQuaid1, and J.M. Gregg1 Centre of nanostructured media, School of Physics and Mathematics, Queen’s University Belfast, University Road, Belfast, United Kingdom, BT7 1NN *e-mail: [email protected] Electric field driven magnetization switching could lead to reductions in power consumption and overheating in current nanoelectronic devices. In this regard, multiferroic magnetoelectric materials are the focus of attention, and in particular room temperature ferroelectric antiferromagnetic bismuth ferrite (BFO) is widely studied due to its unique properties1. It has been shown that in ferromagnetic/(001)pBFO mesostructures electric field driven magnetization rotation can be achieved via an exchange bias mediated interfacial magnetoelectric effect2,3. In order to attain unequivocal control of magnetization in perpendicular heterostructures, deterministic ferroelastic/ferroelectric polarization switching in (001)pBFO firstly needs to be achieved: to this effect investigations are currently ongoing3,4. However, switching procedures in thin films or mesostructures are influenced by the boundary conditions imposed on the area under investigation by the ferroelectric state of the surrounding matrix material5. Therefore, in order to fully understand and control such mechanism in (001)pBFO, it would be desirable to study the phenomenon in free standing nanoislands. Here we apply an ion beam milling fabrication procedure6 to obtain BFO nanoislands out of a thin film. The switching properties are investigated by piezoresponse force microscopy, in relation to size and electrode configuration. Preliminary investigations show that switching is achievable in 250nm and 150nm diameter nanoislands, with good retention properties. However, in order to understand and tune the ferroelectric/ferroelastic switching procedure, polarization control of the structures as a whole is desired, which would require the presence of a top electrode. Such investigations would yield a deeper understanding of the switching mechanism in BFO, and would eventually lead to utilization of composite multiferroics for nanoelectronic devices. 1. Epitaxial BiFeO3 multiferroic thin film heterostructures, Wang J et al., Science 299, p.1719 (2003). 2. Electric-field control of local ferromagnetism using a magnetoelectric multiferroic, Chu Y H et al., Nat. Mat 7, p.478 (2008). 3. Deterministic switching of ferromagnetism at room temperature using an electric field, Heron J T, et al., Nature 516, p.370 (2014). 4. Deterministic control of ferroelastic switching in m ultiferroic materials, Balke N, et al., Nat. Nan. 4, p.868 (2009). 5. Ferroelastic switching for nanoscale non-volatile magnetoelectric devices, Baek S H et al., Nat. Mater. 9, p.309 (2010). 6. Mask assisted fabrication of nanoislands of BiFeO3 by ion beam milling, Morelli A et al., J. Appl. Phys. 113, p.154101 (2013). CV Alesssio Morelli Dr. A. Morelli obtained his PhD from University of Groningen (NL) in 2009 where his research focused on scanning probe microscopy of ferroelectric thin films. He was a postdoctoral research associate in Max Planck Institute, Halle (DE) where his work revolved on multiferroic nanostructures, and in the Institute of Physics, Prague (CZ) on nanoscale characterization of ferroelectric materials. He is currently a Marie Curie fellow at Queen’s University Belfast (UK) within the Centre for Nanostructured Media, with a research project aiming at the investigation of electric field driven magnetization switching in multiferroic nanoislands.
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