双钙钛矿结构中++--型磁结构磁致多铁性及机制研究

项目名称： 双钙钛矿结构中++--型磁结构磁致多铁性及机制研究

项目编号： No.11504419

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 张俊廷

作者单位： 中国矿业大学

项目金额： 20万元

中文摘要： 磁致多铁性材料由于具有本征的强磁电耦合效应近些年来已成为凝聚态物理和材料科学研究的前沿和热点之一。铁电极化小和磁有序温度低是这类多铁性材料目前面临的主要问题，而研究具有交换伸缩机制（常见于++--型磁结构）的新型多铁性材料有希望突破目前的困境。最近实验上首次在双钙钛矿结构（Lu2CoMnO6）中观测到++--型磁结构及多铁性，引起了广泛关注。针对实验结果中存在的争议和困惑，并从寻找新型多铁性材料角度出发，本项目利用第一性原理计算和蒙特卡洛模拟研究在双钙钛矿R2CoMnO6（R=La-Lu,Y）体系中具有++--型磁结构的多铁性材料及存在的多铁性机制。揭示该磁结构诱导铁电极化的物理机制，解释实验上观察到的多铁性现象，并探索该磁结构的起源，寻找该体系中具有++--型磁结构的多铁性材料，预测其铁电性质，为寻找具有大铁电极化和高磁有序温度的磁致多铁性材料提供理论支持。

中文关键词： 多铁性材料；磁致多铁性材料；磁电耦合；第一性原理；双钙钛矿

英文摘要： Magnetic Multiferroics have become the forefront and one of hot topics in the research of condensed matter physics and materials science in recent years due to exhibiting strong intrinsic magnetoelectric coupling. Weak ferroelectric polarization and low magnetic ordering temperature are two important drawbacks of current magnetic multiferroics, while searching for new multiferroics with exchange-striction mechanism (common in ++-- type magnetic structure) is promising for breaking through this predicament. Recently, ++-- type magnetic structure has been first found in double-perovskite Lu2CoMnO6, which attracted considerable attentions. Aiming to solve the problems in experimental results and searching for new multiferroics, this project intends to study the multiferroics with ++-- type magnetic structure and the multiferroic mechanisms among double-perovskite materials R2CoMnO6 (R=La-Lu,Y) using the first principles and Monte Carlo methods. Specific studies include revealing the microscopic mechanism of magnetically inducing ferroelectric polarization, explaining the observed experimental phenomenon of multiferroic, and further researching the origin of this magnetic structure, searching for new multiferroics with ++-- type magnetic structure among this system and predicting the ferroelectric properties of multiferroics. It is hoped that our study will provide theoretical supports for searching for new multiferroics with large ferroelectric polarization and high magnetic ordering temperature.

英文关键词： multiferroics;magnetic multiferroics;magnetoelectric coupling;first principles;double perovskite