For the last few years, the research interest in magnetoelectric (ME) effect, which is the cross-coupling between ferroelectric and magnetic ordering in multiferroic materials, has experienced a significant revival. The extensive recent studies are not only conducted towards the design of sensors, actuators, transducers, and memory devices by taking advantage of the cross-control of polarization (or magnetization) by magnetic (or electric) fields, but also aim to create a clearer picture in understanding the sources of ME responses and the novel effects associated with them. Here we derive analytical models allowing to understand the striking and novel dynamics of ME effects in multiferroics and further confirm it with atomistic simulations. Specifically, the role of strain is revealed to lead to the existence of electroacoustic magnons, a new quasiparticle that mixes acoustic and optical phonons with magnons, which results in resonances and thus a dramatic enhancement of magnetoelectric responses. Moreover, a unique aspect of the dynamical quadratic ME response under a magnetic field with varying frequencies, which is the second harmonic generation (SHG), has not been discussed prior to the present work. These SHGs put emphasis on the fact that nonlinearities should be considered while dealing with such systems.

在最近几年中，对磁电效应的研究兴趣显着复兴，磁电效应是多铁材料中铁电和磁有序之间的交叉耦合。近期广泛的研究不仅通过利用磁场（或电场）对极化（或磁化）的交叉控制来进行传感器，致动器，换能器和存储设备的设计，而且还旨在创造更清晰的环境。理解ME反应的来源以及与之相关的新颖效应的图片。在这里，我们导出分析模型，以了解多元铁磁中ME效应的惊人动态和新颖性，并通过原子模拟进一步确认它。具体来说，揭示了应变的作用导致电声磁振子的存在，一种新的准粒子，它将声子和光学声子与磁振子混合，导致共振，从而显着增强了磁电响应。此外，在当前工作之前，尚未讨论动态磁场二次ME响应在频率变化的磁场下的独特方面，即二次谐波生成（SHG）。这些SHG强调了在处理此类系统时应考虑非线性的事实。