Key Laboratory of Micro & Nano Photonic Structures (MOE), and Shanghai Ultra-precision Optical Manufacturing Engineering Research Center, Department of Optical Science and Engineering, Fudan University, Shanghai, 200433, China.
Basic Experimental Teaching Center, Shaanxi Normal University, Xi'an, 710062, China.
Adv Sci (Weinh). 2023 Feb;10(6):e2205903. doi: 10.1002/advs.202205903. Epub 2023 Jan 3.
Coherent optical control of the magnetization in ferromagnetic (FM) mediums using ultrafast nonthermal effect paves a promising avenue to improve the speed and repetition rate of the magnetization manipulation. Whereas previously, only heat-induced or helicity-dependent magnetization dynamics are demonstrated in metallic ferromagnets. Here, the linearly-polarized light control of magnetization is demonstrated in FM Co coupled with ferroelectric (FE) BiFeO by tuning the light polarization direction. It is revealed that in the Co/BiFeO heterostructure excited by femtosecond laser pulses, the magnetization precession amplitude follows a sinusoidal dependence on the laser polarization direction. This nonthermal control of coherent magnetization rotation is attributed to the optical rectification effect in the BiFeO layer, which yields a FE polarization depending on the light polarization, and the subsequent modulation of magnetic energy in Co by the electrostriction-induced strain. This work demonstrates an effective route to nonthermally manipulate the ultrafast magnetization dynamics in metallic ferromagnets.
利用超快非热效应实现铁磁（FM）介质中磁化强度的相干光学控制，为提高磁化强度操控的速度和重复率开辟了一条很有前途的途径。在此之前，仅在金属铁磁体中证明了热诱导或螺旋依赖的磁化动力学。在这里，通过调整光偏振方向，演示了 FM Co 与铁电（FE）BiFeO 耦合时的线性偏振光对磁化强度的控制。结果表明，在飞秒激光脉冲激发的 Co/BiFeO 异质结构中，磁化进动幅度随激光偏振方向呈正弦依赖关系。这种相干磁化旋转的非热控制归因于 BiFeO 层中的光整流效应，该效应产生了依赖于光偏振的 FE 极化，以及随后由电致伸缩引起的应变对 Co 中磁能的调制。这项工作展示了一种在金属铁磁体中实现非热操控超快磁化动力学的有效途径。
