Surface Acoustic Wave mediated magneto elastic investigation of magnetic thin film systems

声表面波（SAW）是一种非传统的和非常敏感的工具，用于表征薄磁性薄膜的GHz制度。尽管预期SAW的惊人的可能性，只有少数实验已经进行，证明了动态控制自旋系统的可能性。在本提案中，我们将研究在压电铌酸锂衬底上制备的交换偏置铁磁薄膜。我们计划探索磁弹性相互作用与高频声表面波引起的自旋波刺激在sub-GHz制度和影响的磁反转行为。SAW研究的另一个非常有趣的材料系统是非晶铁磁TbFe合金薄膜，它表现出大的磁各向异性和磁致伸缩值。当交换耦合到铁磁层时，磁化反转伴随着界面畴壁的成核和湮灭。我们将研究在声表面波交互作用下的反转过程，包括其磁畴结构。此外，在亚铁磁性稀土过渡金属合金薄膜中，最近发现了由圆偏振飞秒激光脉冲引起的光致磁化反转。在这种情况下，磁化的反转方向仅由光的螺旋度决定，而不是由外部磁场决定。在这里，我们计划结合激光脉冲研究声表面波对超快自旋动力学的刺激。在这种时间分辨的研究中，SAW的内置时钟频率对实验非常有益，并且允许对潜在的相互作用进行频闪测量。

Surface Acoustic Waves (SAW) represent an unconventional and very sensitive tool for the characterization of thin magnetic films up to the GHz regime. Despite the expected stunning possibilities of SAW only few experiments have been carried out that demonstrated the possibility to dynamically control the spin system. In the present proposal, we will investigate exchange-biased ferromagnetic thin films prepared on piezoelectric LiNbO3 substrates. We plan to explore the magnetoelastic interaction with high frequency SAW giving rise to spin wave stimulation in the sub-GHz regime and influencing the magnetic reversal behavior. Another highly interesting material system for SAW studies are amorphous ferrimagnetic TbFe alloy thin films, which exhibit large values of magnetic anisotropy and magnetostriction. When exchange coupled to a ferromagnetic layer, the magnetization reversal is accompanied by the nucleation and annihilation of an interface domain wall. The reversal process including its magnetic domain structure under the impact of SAW interaction will be investigated. Furthermore, in ferrimagnetic rare earth transition metal alloy films, optically induced magnetization reversal induced by circularly polarized femtosecond laser pulses was recently discovered. In this case, the reversal direction of magnetization is determined solely by the helicity of the light and not by an external magnetic field. Here, we plan to study the stimulus of SAW on ultra-fast spin dynamics in combination with laser pulses. In such time-resolved investigations the built-in clock frequency of the SAW is very much beneficial to the experiment and permits virtually stroboscopic measurements of the underlying interaction.