Magnetoelectric resonance with electromagnons in a perovskite helimagnet
Magnetoelectric resonance with electromagnons in a perovskite helimagnet
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DOI：
10.1038/nphys2161
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发表时间：
2012-02-01
期刊：
影响因子：
19.6
通讯作者：
Tokura, Yoshinori
中科院分区：
文献类型：
--
作者：
Takahashi, Youtarou;Shimano, Ryo;Tokura, Yoshinori
麦克斯韦方程描述了给定介质中随时间变化的电场（E）和磁场（H）之间的相互关系。在表现出相对论性自旋轨道相互作用的材料中，我们也期望它们的极化（P）和磁化（M）动态耦合。这反过来又可以在光子器件的开发中更好地控制光的电场和磁场之间的交叉耦合（1）。这种磁电现象预计将在支持电磁子的材料中得到增强，电磁子是表现出电和磁偶极矩的基本激发。在这里，我们报告发现的钙钛矿（Eu; Y）MnO 3，这是由摆线自旋顺序（2-5）产生的自发极化的波动。由此产生的动态M-P交叉耦合导致材料在与这些激发相关的共振频率（亚太赫兹）下表现出巨大的方向二向色性-在相反方向传播的光的吸收差异。
Maxwell's equations describe the interrelation between temporally changing electric (E) and magnetic (H) fields in a given medium. In materials that exhibit relativistic spin-orbit interactions, we also expect their polarization (P) and magnetization (M) to be dynamically coupled. This in turn could enable greater control over the cross-coupling between the electric and magnetic fields of light in the development of photonic devices(1). Such magnetoelectric phenomena are expected to be enhanced within materials that support electromagnons-fundamental excitations that exhibit both electric and magnetic dipole moments. Here we report the discovery of electromagnons in the perovskite (Eu; Y)MnO3, which arise from fluctuations in the spontaneous polarization generated by cycloidal spin order(2-5). The resulting dynamical M-P cross-coupling causes the material to exhibit colossal directional dichroism-a difference in the absorption of light propagating in opposite directions-at the resonance frequency (sub-THz) associated with these excitations.