Date(s) - 29 Nov 2018
3:00 PM - 4:00 PM
1227 Hoover Hall
Speaker: Zhongming Fan, Graduate Student with the Department of Materials Science and Engineering at Iowa State University
Title: Antiferroelectrics: Microstructure and Phase Transformations
Abstract:Unlike polar ferroelectrics (FE), antiferroelectric (AFE) materials do not display any net polarization. It has been well accepted that the antiparallel dipole arrangement in AFE domain accounts for the non-polar nature. In my thesis research, aberration corrected HAADF-STEM and associated image analysis tools are employed to directly reveal the dipole moment, so that the antiparallel dipole arrangement is proved. At the larger spatial range of grains, planer defects like domain boundaries and stacking faults render the microstructure in AFEs even more complicated, which have been systematically investigated and analyzed. For AFEs in the bulk form, on the other hand, the AFE↔FE phase transformation induced by temperature/stress/applied E field has received the most research efforts. In the last part of this talk, experimental results on the AFE↔FE phase transformation driven by a new stimulus, the internal depolarization field, will be presented.