Lecture Weida Wu
|01 August 2012||FWN-Building 5115.0017, Nijenborgh 4, 9747 AG, Groningen|
|Speaker:||Prof. Dr. Weida Wu|
|Affiliation:||Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, NJ, USA|
|Title:||Magnetism at ferroelectric domain walls in multiferroic hexagonal manganites|
|Date:||Wed Aug 1, 2012|
|Telephone:||+31 50 363 3419|
Topological defects are pervasive in complex matter such as superfluids, liquid crystals, and early universe. They have been fruitful playgrounds for many emergent phenomena. Recently, vortex-like topological defects with six interlocked structural antiphase and ferroelectric domains merging into a vortex core were revealed in ferroelectric hexagonal manganites . Numerous vortices are found to form an intriguing self-organized network, where charged domain walls with emergent properties are protected. Using cryogenic magnetic force microscopy (MFM) in applied magnetic fields and ambient piezo-response force microscopy (PFM), we discovered that the alternating domain wall magnetizations around vortices can correlate over the entire vortex network in ErMnO3 . The “collective” nature of the domain wall magnetism appears originated from the uncompensated Er3+ moments at domain walls, the field-controllable spin state of antiferromagnetic domains, and the correlated organization of the vortex network. Our results demonstrate a new route for nanoscale magnetoelectric coupling in single-phase multiferroics, and open the possibility of detecting spin state by harnessing domain wall magnetism.
 T. Choi et al., Nature Materials 9, 253 (2010).
 Y. Geng, N. Lee, Y. J. Choi, S.-W. Cheong, and W. Wu, arXiv:1201.0694 (2012).
|Last modified:||22 October 2012 2.30 p.m.|