IMF2017

BiFeO₃-based solid solutions, i.e., BiFeO₃-ABO₃, have been extensively studied for multiferroic behavior by manipulating the crystal structure and coupling between the ferroelectric order and magnetic order. Taking two different approaches, namely epitaxial straining and cation substitution (on either A-site or B-site or both sites), we have developed a series of BFO-based solid solutionsof perovskites structure as a class of important Pb-free electroceramics. Interestingly, several different crystal structures and therefore ferroelectric and piezoelectric behavior are realized. A particularly interesting structure is the super-tetragonal (T) phase, which can well be retained by chemical doping, such as Ga substitution for Fe in BFO, where BiFe_0.6Ga_0.4O₃is a good example. Investigations into the ferroelectric behavior, by both global property measurement, such as P-E, and local PFM studies, support a new type of microscopic origin of ferroelectric polarization from the ion displacement induced dipole moments. In addition to the multiferroic behavior, a newly emerging function of BiFeO₃-basedthin films is the photovoltaic behavior, which can well be tuned and much enhanced by both chemical doping and formation of proper heterolayers, examples of which are In₂O₃-SnO₂/ZnO/BiFeO₃/Pt and In₂O₃-SnO₂/BiFe_0.6Sc_0.4O₃/LaNiO₃. In this talk, we will report the latest development of BiFeO₃-based solid solutions for both multiferroric and photovoltaic applications.