会员注册 会员登录  国资委专项基金建设平台  咨询热线:010-65761182 主办:建筑材料工业技术情报研究所 国家建材技术图书馆   借阅卡 联系我们
微信关注
2528bmi001_1T
1314web_logo
首页 新闻资讯 会议会展 视频培训 图书 期刊 外文期刊 报纸 标准 专利 成果 产品 企业 知识进厂
您所在的位置:首页>>论文报告
Phase transformations in the relaxor Na1/21/2Bi1/21/2TiO33studied by means of density functional theory calculations
【文件类型】 【消费金额】0.3 【文章页数】1 【会员操作】  
【文章作者】Meyer Kai‐Christian;Koch Leonie;Albe Karsten
【文章摘要】      Abstract

The relaxor material Na1/2Bi1/2TiO3(NBT) is an important basis for the development of lead‐free piezoceramics, but still many features of this material are not well understood. Here, we study the kinetics of phase transformations by octahedral tilts and A‐cation displacements in NBT by means of density functional theory calculations, employing ab initio molecular dynamics and nudged elastic band calculations. Our results show that the energetic differences between the low temperature rhombohedral, intermediate orthorhombic and other metastable phases are close to the room temperature thermal energy. Therefore, it is likely that above room temperature, several octahedral tilt patterns are present simultaneously on the local scale, just because of thermal vibration of the oxygen ions. Octahedral tilt transformations and A‐cation displacements show similarly high energy barriers, however, since the vibrational frequency of oxygen is higher, tilt transformations occur more frequently. Further, tilt transformations in which the oxygen octahedra get deformed the least are more probable to occur. We also find that the chemical A‐cation order affects energy barriers, influences the coupling between rotational and displacive modes and determines the stability of certain octahedral tilt orders. We conclude that the so‐called polar nanoregions in this material result from local octahedral tilt transformations and subsequent A‐cation displacements, which are driven by thermal vibration and are mediated by the underlying chemical order.

【关 键 字】
【卷】101【ISSUE】1【ISSUEID】815B0005    【文章期份】2018    【发布日期】2018/8/28 16:25:08    点击率:0    打印    关闭
首页 新闻资讯 会议会展 视频培训 图书 期刊 外文期刊 报纸 标准 专利 成果 产品 企业 知识进厂
网络市场部:010-65761182 网络技术部:010-51164639  传真:010-65761182 Email:service@chinabmi.com
在线服务 QQ:  
建筑材料工业技术情报研究所 国家建材技术图书馆
京ICP备06002939号 京ICP备000046
Copyright © 2004 chinabmi.com All rights reserved. 中国建材智网版权所有