Subkhangulov R R, Henriques A B, Rappl P H O, Abramof E, Rasing Th, Kimel A V
Radboud University Nijmegen, Institute for Molecules and Materials, 6525 AJ, Nijmegen, The Netherlands.
Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, CEP 05315-970 Sao Paulo, Brazil.
Sci Rep. 2014 Mar 24;4:4368. doi: 10.1038/srep04368.
We demonstrate that the ultrafast fast dynamics of the d-f exchange interaction, between conduction band electrons and lattice spins in EuTe, can be accessed using an all-optical technique. Our results reveal, in full detail, the time evolution of the d-f exchange interaction induced by a femtosecond laser pulse. Specifically, by monitoring the time resolved dynamics of the reflectivity changes and Kerr rotation of a weak light pulse reflected from the surface of the sample, it is shown that an intense femtosecond light pulse with photon energies higher than that of the bandgap, triggers spin waves in EuTe. The laser-induced spin waves modulate the d-f exchange interaction, and cause the bandgap to oscillate with an amplitude reaching 1 meV, at frequencies up to tens of GHz. The ability to control and monitor the dynamics of the exchange energy with our all-optical technique opens up new opportunities for the manipulation of magnetism at ultrafast time-scales.
我们证明，利用全光技术可以研究EuTe中导带电子与晶格自旋之间d-f交换相互作用的超快动力学。我们的结果详细揭示了飞秒激光脉冲诱导的d-f交换相互作用的时间演化。具体而言，通过监测从样品表面反射的弱光脉冲的反射率变化和克尔旋转的时间分辨动力学，结果表明，光子能量高于带隙的强飞秒光脉冲会在EuTe中引发自旋波。激光诱导的自旋波调制d-f交换相互作用，并使带隙以高达1 meV的幅度振荡，频率高达数十GHz。我们的全光技术能够控制和监测交换能的动力学，为在超快时间尺度上操纵磁性开辟了新的机会。
