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理学院“青年学术论坛”第33期讲座题目: Multiferroics：A twist to achieve electrical control of multiple ferroic orders 报告人：张金星研究员主持人：吴真平讲师时间：2014年12月5日（周五）上午10：00-11：00 地点：主楼1214 报告内容简介：Due to the upcoming demands of the next-generation electronic devices with low energy consumption, high storage density and high write-read speed, emerging correlated materials and structures (such as superconductivity- based systems, topological Insulators, magnetoelectric multiferroics etc.) are highly desired. Recently, especially for the last decades,multiferroics attract people’s interests due to their relatively high transition temperature and being chemically robust at ambient atmosphere. These give people a strong push to explore coupling between magnetic and ferroelectric order parameters in multiferroics. Among the natural and artificial compounds, BiFeO3 (BFO) is one of the most promising materials due to its high ferroelectric and antiferromagnetic transition temperature. In this talk, I will firstly give an introduction about crystal, polar and spin structures of BFO,and how the spin and polar can couple each other in its ground state and highly strained states. Based on this understanding, I will talk about the strong magnetoelectric coupling in BFO-related systems at reduced dimensions (e.g. heterointerface, domain walls, and phase boundary etc.). Taking advantage of this multiferroic model system, we are able to have opportunities to better understand the emerging coupling in other ferroic materials. In the last part of my talk,I will briefly introduce a brand-new strategy to deterministically switch the ferroelectric polarization using H2O in large scale. Emerging phenomena has been analyzed across the liquid/ oxide interface. These reversible controls of the electric, magnetic and elastic order parameters demonstrate possible applications in future electronic and magnetoelectronic devices. 报告人简介：张金星，男，1981年5月生，博士生导师，研究员。2009 年12 月毕业于香港理工大学应用物理系并获理学博士学位，其中2008 年8 月到2009 年11 月在加州大学伯克利分校材料系访问研究并在伯克利完成博士论文。博士毕业后留在加州大学物理系从事博士后研究（合作导师R.Ramesh教授）。2012年2月入选中组部第二批青年千人计划，被北京师范大学以海外高层次人才引进，目前为北京师范大学物理系研究员。2013年9月获得国家自然基金委优秀青年基金。在北京师范大学和加州大学伯克利分校期间，张金星的主要研究方向是过渡金属氧化物薄膜的外延生长，关联体系尤其纳米尺度下表面界面处新奇特性的探测与调控，及其在信息技术、能源转化、传感驱动等方面的应用。已取得了一系列创新成果。近五年来，在中国国家自然基金委以及美国Intel公司资助下，已以第一作者及通讯作者在Nature Nanotechnology（1篇），Nature Communications（1篇），Physical Review Letters（1篇），Scientific Report（1篇）等重要期刊发表和接受论文10余篇，其中包括受邀请在Nanoscale上撰写1篇Review Article。并以主要作者和合作作者在Science, Nature Materials, Nature Nanotechnology，Physical Review Letters, Proceedings of National Academy of Science上发表和接收论文20余篇。5年共发表论文30余篇，SCI引用1300次左右。曾多次在相关领域的重要国际大会上做口头报告。2008年第13届香港物理学会获得Outstanding Presentation Award,2011年获美国MRS春季会议Outstanding Poster Award。 Recent selected publications 1.Jinxing Zhang*, Xiaoxing Ke, Gaoyang Gou, Jan Seidel, Bin Xiang, Pu Yu, Wen-I. Liang, Andrew M. Minor, Ying-Hao Chu, Gustaaf Van Tendeloo, Xiaobing Ren, Ramamoorthy Ramesh, “A nanoscale shape memory oxide”, Nature Communications 4, 2768 (2013). 2.M. Liu, J. Hoffman,J. Wang,J. X. Zhang*, N.-C, Brittany, A. Bhattacharya*, “Non-volatile ferroelastic switching of the Verwey transition and resistivity of epitaxial Fe3O4/PMN-PT (011)”, Scientific Reports 3, 1876 (2013). 3. J. X. Zhang*,Q.He,Y.-H. Chu, and R.Ramesh,“Nanoscale phase boundary: a new twist for novel functionalities”, Nanoscale(invited review) 4, 6196 (2012). 4.J. X. Zhang*,B.Xiang, Q. He, J. Seidel,R.J. Robert, P. Yu, S.Y.Yang,C.H. Wang, Y.-H. Chu, L.W.Martin, A.M. Minor,and R. Ramesh,“Large field-induced strains in a lead-free piezoelectric material”,Nature Nanotechnology, 6, 98 (2011). 5. J. X. Zhang*, Q. He, M. Trassin, W. Luo, D. Yi, M. D. Rossell, P. Yu, L. You, C. H. Wang, C. Y. Kuo,J. T. Heron, Z. Hu,R.J.Zeches,H.J. Lin, A. Tanaka, C. T. Chen, L. H. Tjeng, Y.-H. Chu, R. Ramesh,“Microscopic origin of giant ferroelectric polarization in tetragonal-like BiFeO3”, Physical Review Letters, 107, 147602 (2011). Funding sources: 此类研究主要受中组部青年千人计划启动基金、国家自然基金委优秀青年基金、面上基金、重点基金，以及科技部973计划等项目支持。 http://portal.bupt.edu.cn//html/main/col38/2014-12/03/20141203160931756648600_1.html