报告人简介：

同济大学功能材料研究所教授，现从事高温单相磁电、压电多重铁性功能材料物理和纳米铁电材料物理研究。曾主持国家自然科学基金青年基金和上海市自然科学基金各1项。个人荣获2004年度德国洪堡学者，2004-2006年度日本学术振兴会外国人特别研究员，2007  年获教育部新世纪优秀人才计划和上海市浦江人才计划等项目资助。

报告摘要：

Since 2011, materials genome approach has been speeded up applying to  accelerate material innovations including pace of both discovery and deployment  of advanced materials. The genome of material is atom and its electronic  structure. The theoretical bases of materials genome approach are Periodic Table  of Elements and Lattice Symmetry. Dalton’s atomic theory set foundation of atom  of elements for chemical combination and physical structural phase  transition---rearrangement of atom. Its purpose is to design novel materials in  a predictable way other than in an alchemical (‘cooking’) way.

Perovskite-type ferroelectrics are one of most important functional  materials, of which ferroelectric Curie temperature (TC) and piezoelectric  response are closely dependent on its composition and lattice symmetry. In this  talk, materials genome approach is used to analyze the determining factors of  Curie temperature (TC) and piezoelectric constant (d33) in a quantitative way  within the database of perovskite-type ferroelectrics. Two relationships of μ is  reduced mass of ABO3 unit cell)1,2 and (ε33 is dielectric constant after poling  ceramics)3,4 are obtained through fitting known data and interpreted well  relating to mass and size of atom (‘genome of material’) within structural phase  transition and dielectric theories, respectively. Based on the above two  relationships and structural phase boundary for high piezoresponse,  perovskite-type BiFeO3-Bi(Zn1/2Ti1/2)O3-PbTiO3 and BiFeO3-Bi(Zn1/2Ti1/2)O3-  BaTiO3 ternary systems were chosen and experimentally studied as potential  candidates for novel ferroelectrics with higher Curie temperature and  piezoresponse than tungsten bronze-type PbNb2O6 and Aurivillius-type Bi4Ti3O12  ferroelectrics.3-5 The structural phase boundary was determined by powder X-ray  diffraction and found strongly influenced by ceramic grain size. The structural  phase boundary is intrinsically benefiting for high piezoresponse but residual  internal stresses play extrinsic role to pin ferroelectric polarization  switching and cause non-full poling treatment for the BZT-riched ceramics.  Judged by , full piezoresponse was able to set in ceramics, excellent thermal  and time aging stability of piezoelectric constant d33 were demonstrated  contemporarily in BF-BZT-BT system.5 The residual internal stresses were argued  resulting from one intermediate phase with negative thermal expansion  coefficient recently discovered in BiFeO3-based ternary system and could be  eliminated by post heat treatment.6 BF-BZT-BT and BF-BZT-PT are becoming  promising candidate for future lead-free applications or high temperature  applications because extended structural phase boundary provides big space to  adjust piezoelectric performance and aging stabilities by changing composition.  Our essay shows the data-driven materials genome approach much efficient in  designing novel ferroelectric piezoceramic materials.