Giant Improper Ferroelectricity in the Ferroaxial Magnet CaMn7O12
Giant Improper Ferroelectricity in the Ferroaxial Magnet CaMn7O12
复制标题
DOI：
10.1103/physrevlett.108.067201
复制
发表时间：
2012-02-06
影响因子：
8.6
通讯作者：
Martin, C.
中科院分区：
文献类型：
--
作者：
Johnson, R. D.;Chapon, L. C.;Martin, C.
在斜方相CaMn7O12中，在T-n1=90K以下演化的无公度螺旋磁结构引起了2870µcm-2的不适当的铁电极化，电极化被约束在晶体结构的高对称性三重旋转轴上，垂直于磁矩的面内旋转。多铁性可以用铁轴耦合机制来解释，在CaMn7O12中产生了迄今为止测量到的最大的磁感应电极化。
In rhombohedral CaMn7O12, an improper ferroelectric polarization of magnitude 2870 mu Cm-2 is induced by an incommensurate helical magnetic structure that evolves below T-N1 = 90 K. The electric polarization was found to be constrained to the high symmetry threefold rotation axis of the crystal structure, perpendicular to the in-plane rotation of the magnetic moments. The multiferroicity is explained by the ferroaxial coupling mechanism, which in CaMn7O12 gives rise to the largest magnetically induced, electric polarization measured to date.