Multiferroics represent an outstanding 21st century challenge toward next generation electronics, due to the exciting prospect of combining magnetism and electrical polarization in a single compound with true spin-charge coupling. In our lab, the goal is to use chemical solution processing to attempt to develop new single phase multiferroics with overlapping magnetic and electrical properties closer to room temperature. The target materials present magnetic and electrical properties of fundamental and commercial interest. Seeking and detecting potential magnetoelectric coupling in novel multiferroic complex oxides is an underlying, long term challenge, with many important research and education goals along the path.
Progress in multiferroics has been limited by physical restrictions on the co-existence of magnetic (Mi) or electrical polarization (Pi) in a single compound, and the magnitude of magnetoelectric coupling, αij. Recent research happening across the globe suggest that there are opportunities, both theoretically and experimentally, for placing lower constraints on the coexistence of ferroelectricity with ferromagnetism. We use Gel-collection, as an effective synthetic method for producing complex transition metal oxides that are multiferroic and/or high dielectric in nature, some of which are brand new.
Related Publications
1. Lombardi, J.; Pearsall, F.; Li, W.; O'Brien, S. “Synthesis and dielectric properties of nanocrystalline oxide perovskites, [KNbO3]1−x[BaNi0.5Nb0.5O3−δ]x, derived from potassium niobate KNbO3 by gel collection” J. Mater. Chem. C, 2016, 4, 7989-7998.
2. Liu, S.; Huang, L.; Wanlu Li, W.; Xiaohua Liu, W.; Shui, J.; Li, J. and O'Brien, S. “Green and scalable production of colloidal perovskite nanocrystals and transparent sols by a controlled self-collection process”, Nanoscale, 2015, 7, 11766. DOI: 10.1039/c5nr02351c.
3. Hossain, M. E.; Liu, S.; O’Brien, S.; Li, J. “Frequency-dependent ferroelectric behavior of a new class of hollandite complex nanocrystals - BaMn3Ti4O14.25 at room temperature,” Applied Physics Letters, 2015, 107, 032904, doi: 10.1063/1.4927246.
4. Liu Shuangyi, L.; Li, W.; Li J., O'Brien S., "Electrical Properties of New Hollandite Complex Oxide Nanocrystals." Journal of nanoscience and nanotechnology 2015, 15 (9), 7074-80.
5. Liu, S.; Akbashev, A. R.; Yang, X.; Liu, X.; Li, W.; Zhao, L.; Li, X.; Couzis, A.; Han, M.-G.; Zhu, Y.; Krusin-Elbaum, L.; Li, J.; Huang, L.; Billinge, S. J. L.; Spanier, J. E.; O’Brien, S. “Hollandites as a new class of multiferroics,” Nature Scientific Reports, 2014, doi:10.1038/srep06203.