| AVS 60th International Symposium and Exhibition | |
| Magnetic Interfaces and Nanostructures | Tuesday Sessions |
| Session MI+AS+NS+SP-TuA |
| Session: | Advanced Probes in Magnetic Imaging and Characterization |
| Presenter: | W. Wu, Rutgers University |
| Authors: | W. Wu, Rutgers University Y. Geng, Rutgers University X. Wang, Rutgers University S-W. Cheong, Rutgers University C.J. Fennie, Cornell University M. Mostovoy, University of Groningen, Netherlands |
| Correspondent: | Click to Email |
The coupling between the magnetic and electric dipoles in multiferroic and magnetoelectric materials holds promise of conceptually new electronic devices1-4. The device miniaturization calls for development of local probes of the magnetoelectric response, in particular because such response is strongly affected by defects in magnetic and ferroelectric orders. For example, multiferroic hexagonal rare earth manganites exhibit a dense network of boundaries between six degenerate states of their crystal lattice, which are locked to both ferroelectric and magnetic domain walls. Here we present the first application of a newly-developed Magnetoelectric Force Microscopy (MeFM), which combines Magnetic Force Microscopy (MFM) with in-situ modulating high electric fields. This technique allowed us to directly image the magnetoelectric response of the domain patterns in hexagonal manganites. We found that this response changes sign at each structural domain wall. This MeFM result is corroborated by a symmetry analysis and a phenomenological model derived from microscopics and first-principles calculations5, providing compelling evidence for a lattice-mediated magnetoelectric coupling. Furthermore, our measurements reveal a diverging magnetoelectric response near a critical point below 2 K originating from enhanced critical fluctuations and the high sensitivity of spin ordering to applied electric and magnetic fields. The direct visualization of magnetoelectric domains at mesoscopic scales opens up explorations of emergent phenomena in multifunctional materials with multiple coupled orders.
1. Eerenstein, W., Mathur, N. D., and Scott, J. F., Nature 442 (7104), 759 (2006).
2. Ramesh, R. and Spaldin, N. A., Nature Materials6 (1), 21 (2007).
3. Cheong, S. W. and Mostovoy, M., Nat. Mater.6 (1), 13 (2007).
4. Spaldin, N. A., Cheong, S.-W., and Ramesh, R., Physics Today (2010).
5. Das, H., Wysocki, A. L., and Fennie, C. J., arXiv:1302.1099 (2013).