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磁学室学术报告（2014-1）

来源：admin 发布时间：2016-06-17

题目:	[磁学室学术报告] Strains and Domains in Multiferroic Oxides
时间:	2014年01月15日 10:00
地点:	物理所M楼249会议室
报告人:	Wei Ren 任伟
Department of Physics, Shanghai University, 99 Shangda Road, Shanghai 200444, China 上海大学物理系报告摘要： Epitaxial strain arising from the lattice mismatch between oxide films and substrates has been shown to dramatically enhance physical properties of single-domain mulitiferroic system. For instance, a large compressive strain applied on (001)-oriented BiFeO3 (BFO) can induce the ferroelectric polarization transition from [111] to nearly [001] direction, the coexistence of two phases (R-like and T-like) across a morphotropic phase boundary, the appearance of huge tetragonality c/a ratio and five-fold coordinated Fe atoms. Moreover, domain walls (DW) separating ferroelectric domains of different polarities have also been ubiquitously observed in BFO materials. Such domains and their walls (corresponding to ideal angles of 71°, 109°, and 180° formed by the domain polarizations) have a profound influence on the multifunctional performances of BFO, including nonvolatile random access memories, piezoelectric devices, electronic transport, and above-band gap photovoltaic effect, to name a few. We have investigated the energetic, electric and magnetic characteristics of ferroelectric BFO bulk and BFO domains subject to epitaxial strain. Furthermore, we compare some strain effects with that of chemical and hydrostatic pressures. We will also introduce novel domains defined by an important order parameter other than polarizations. References: Phys. Rev. Lett., 110, 187601 (2013); Phys. Rev. Lett., 109, 057602 (2012). Adv. Funct. Mater., 23, 234 (2013); Phys. Rev. Lett., 109, 267602, (2012). 报告人简介： Wei REN received his Ph.D. in 2006 from The University of Hong Kong. After a postdoc position at Hong Kong University of Science and Technology, he moved to University of Arkansas as a research associate and research assistant professor from 2008 to 2012. Now, he is a professor in Physics Department of Shanghai University. His research areas include multiferroics, quantum transport and first-principles computation, and he has published 54 articles on prestigious journals such as 1 in Nature Physics, 1 in Nature Communications, 8 in Physical Review Letters, 1 in Advanced Materials, 1 in Advanced Functional Materials, 18 in Physical Review B etc. As a principle investigator, he has been awarded by NSF of China, Shanghai Eastern Scholar Professorship, Shanghai Shuguang Program, Innovation Fund of Shanghai University, and has also participated in the Shanghai 085 Materials Genome Project. 联系人：闫丽琴联系电话： 82649088