Femtosecond activation of magnetoelectricity
Femtosecond activation of magnetoelectricity
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DOI：
10.1038/s41567-017-0036-1
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发表时间：
2018-04-01
期刊：
影响因子：
19.6
通讯作者：
Kuwata-Gonokami, M.
中科院分区：
文献类型：
--
作者：
Bossini, D.;Konishi, K.;Kuwata-Gonokami, M.
在磁电和多铁性材料中，磁场自由度可以由电场控制，反之亦然。大量的研究致力于利用直流电场驱动的磁电数据存储和操作设备的这种效应（1-4）。针对越来越快的磁电操纵方案，一种有前途的替代方法在飞秒时间尺度上提供了类似的控制，依赖于激光脉冲（4-6）来控制固体的电荷（7，8）和磁性（9，10）顺序。在这里，我们光诱导的磁电性和多铁性在亚皮秒的时间尺度上的CuB 2 O 4。这一过程是由布里渊区边缘附近的波矢产生高能磁激发-磁振子的共振光激发触发的。光激发最显著的结果是光的吸收变得非互易，这意味着材料对光的两个相反传播方向表现出不同的透明度。光生磁电在皮秒时间尺度上没有衰减。我们的研究结果揭示了多铁性材料中电荷和自旋之间内在耦合的超快操纵路径（4），这可能揭示未探索的磁性配置，并揭示飞秒磁性光学控制方面的新功能。
In magnetoelectric and multiferroic materials, the magnetic degree of freedom can be controlled by electric field, and vice versa. A significant amount of research has been devoted to exploiting this effect for magnetoelectric data storage and manipulation devices driven by d.c. electric fields(1-4). Aiming at ever-faster schemes of magnetoelectric manipulation, a promising alternative approach offers similar control on a femtosecond timescale, relying on laser pulses(4-6) to control both the charge(7,8) and the magnetic(9,10) order of solids. Here we photo-induce magnetoelectricity and multiferroicity in CuB2O4 on a sub-picosecond timescale. This process is triggered by the resonant optical generation of the highestenergy magnetic excitations-magnons with wavevectors near the edges of the Brillouin zone. The most striking consequence of the photo-excitation is that the absorption of light becomes non-reciprocal, which means that the material exhibits a different transparency for two opposite directions of propagation of light. The photo-induced magnetoelectricity does not show any decay on the picosecond timescale. Our findings uncover a path for ultrafast manipulations of the intrinsic coupling between charges and spins in multiferroics(4), which may reveal unexplored magnetic configurations and unravel new functionalities in terms of femtosecond optical control of magnetism.