Spin wave excitation by spin-polarized electric current in all-metallic and tunnel magnetic junctions

点击翻译按钮获取中文摘要

Current induced magnetic switching describing the change in the direction of magnetization of a magnetic film due to interaction of spin-polarized conduction electrons with the film's magnetic moments is considered now as a potential switching mechanism for next generations of magnetic memory. This interaction, however, should also lead to the amplification of non-uniform excitations. The subject of the project is to investigate the process of spin wave excitation and amplification caused by the spin polarized current. The experiment will be realized in metallic magnetic layered systems with anti ferromagnetic interlayer coupling: spin waves will be excited by an ac current of microwave frequency in a specially designed MW cavity allowing for a spatial separation of electric and magnetic fields. Thus, the parasitic effect of spin wave excitation by the MW magnetic field, unavoidable in point contact experiments, will be excluded. A spatial modulation of the spin polarized current will generate spin waves of well defined wave vector. Using short pulses of electric current and time resolved Brillouin light scattering spectroscopy the dynamics of the excitation process will be studied. Changing the time delay between the current pulse and the time moment of the spin wave detection, the growth of the spin wave intensity due to interaction with the current pulse and their consequent decay will be investigated.