Complex oxide heterostructures and multiferroics
Date : June 5, 2013 16:00 ~
Speaker : Prof. Yang Chan-ho(Physics/KAIST)
Professor :
Location : 56동106호
Complex transition metal oxides have attracted a lot of attention because of versatile phenomena and rich physics due to a competition between strongly correlated states with different spin, orbital, and charge. Since the discovery of high T¬c superconductivity, many efforts to synthesize complex oxide compounds in epitaxial film form have been made. We now know basic rules about experimental techniques and materials design. In the talk, I will introduce laser molecular beam epitaxy (L-MBE) technique for growing oxide thin layers with atomic precision and discuss why such epitaxial growths would bring interesting physics. As an example, I will focus on a highly-elongated bismuth ferrite with a high tetragonal factor (c/a ~ 1.26) which is a meta-stable phase competing with the multiferroic bismuth ferrite phase. It is never made in bulk form, but it can be stabilized by hetero-epitaxial growth on special substrates owing to misfit strain. Stabilization of such a meta-stable state gives us another chance to search for new materials. The delicate nature of phase competition and the physical properties of the new meta-stable phase will be presented.