能源与材料创新研究院学术报告:Rare-earth-substituted BiFeO3 : spice up the‘holy grail’of multiferroics

发布者:金霞发布时间:2017-05-17浏览次数:51

报告题目:Rare-earth-substituted BiFeO 3 : spice up theholy grailof multiferroics

人:许彬博士美国 University of Arkansas

报告时间:20170523日(星期二)8:30

报告地点:能源与材料创新研究院一楼学术报告厅115

报告简介:

Multiferroics form an important class of materials that possess coupled long-range-orderedelectric and magnetic degrees of freedom.Such magneto-electric coupling is promising fordesigning new devices taking advantage of the control of magnetic properties by theapplication of an electric field; or vise versa. The most studied multiferroic to date is bismuthferrite (BiFeO 3 or BFO) because it exhibits a large spontaneous polarization (~90 µC/cm 2 )with a high Curie temperature (T C ≈ 1100 K) as well as possesses a magnetic ordering (whichconsists of a G-type based cycloid in the bulk) with a Néel temperature T N ≈ 640 K, thereforerendering it a room-temperature multiferroic and being denominated as “the holy grail ofmultiferroics”.

Interestingly, novel multiferroic properties can be achieved combining BiFeO 3 with RFeO3(R is a rare earth element). Using an effective Hamiltonian scheme and Monte Carlosimulation, we study the finite-temperature properties of rare-earth-substituted BiFeO 3(BRFO, with R=Nd in this work) in both disordered (solid solution) and ordered (1/1superlattice, hybrid improper ferroelectric) forms, and remarkably, I will show that theapplied electric-field can trigger a paramagnetic-to-antiferromagnetic transition in BNFOsolid solutions, while it can control the direction of the weak ferromagnetization in BFO/NFO1/1 superlattice.

In addition, I will discuss a lead-free system for high-power energy storage based onantiferroelectric BRFO systems, which potentially allow high energy densities (100–150 Jcm -3 ) and efficiencies (80–88%) for electric field that is within the range of feasibility uponexperimental advances (2–3 MV cm -1 ). A simple model is further derived to describe theenergy density and efficiency of a general AFE material, providing a framework to assess theeffect on the storage properties of variations in doping, electric field magnitude and direction,epitaxial strain, temperature and so on, which can facilitate future search of AFE materials forenergy storage.

 

报告人简介:许彬,凝聚态物理学博士。2003年本科毕业于中国科技大学,2009年获得美国Auburn University博士学位。博后先后就职于美国University of Texas at Arlington(1年),比利时University of Liège(3年),美国 University of Arkansas(2014年至今)。长期从事多铁、铁电、输运以及高压等领域的计算物理研究。目前已在PRL, Nature Commun., Adv. Funct. Mater., PRB等有国际影响力的期刊发表第一或通讯作者论文多篇。长期担任PRL, PRB, Nature Commun., Adv. Mater.等国际知名期刊审稿人。