主 讲 人 ：柴一晟 教授
活动时间：11月26日16时30分
地 点 ：理科群2号楼B509
讲座内容：
Two multiferroic hexaferrites Y-type Ba0.5Sr1.5Zn2(Fe0.92Al0.08)12O22 and Z-type Ba0.52Sr2.48Co2Fe24O41 have been reported to show giant electric field control of magnetization and small magnetic field control of drastic change of polarization, i.e., giant magnetoelectric (ME) effects up to room temperature. However, it is still a mystery that their ME properties are quite different in many aspects even though they have very similar transverse cone spin configurations. Here, we report the comparative investigation of angle-dependent ME effects in two compounds. When the external H is rotated clockwise by 360°, the in-plane P vector is rotated clockwise by 360° in the Y-type hexaferrite and counterclockwise by 720° in the Z-type hexaferrite. These contrasting ME effects can only be explained with a new symmetry-based spin model and tensor analysis. Our new approach reveals that the faster and opposite rotation of the P vector in the Z-type hexaferrite is associated with the lack of the space inversion in one of the magnetic blocks. Moreover, such a peculiar crystal symmetry also results in contrasting microscopic origins for the spin-driven ME behaviors; only the inverse DM interaction is responsible for the Y-type hexaferrite while additional p-d hybridization becomes more important in the Z-type hexaferrite. This work demonstrates the importance of the crystal symmetry in the determination of ME properties in the hexaferrites and provides a fundamental framework for understanding and applying the ME properties in other spin-driven multiferroics.
主讲人介绍：
柴一晟，重庆大学物理澳门官方游戏网站教授，博士生导师。1995-2007年，本科、硕博连读于中国科学技术大学物理系；2004-2005年，丹麦Risoe国家实验室访问学者；2007-2012年，韩国国立首尔大学物理系博士后；2012-2017年，中科院物理所磁学室副研究员。2017年至今，重庆大学物理澳门官方游戏网站教授。长期从事：1、单相与复合多铁、磁电耦合行为研究；2、超导与强关联系统研究；3、热输运测量、强磁场测量及其它磁性测量方法的发展。SCI文章114篇，它引2,345，H因子31。
