Detection of DC voltages in multi-layered magnetic thin films undergoing ferromagnetic resonance

Summary form only given. In 1996, Berger (Phys. Rev. B vol. 54, p. 9354, 1996) predicted that a DC current crossing an interface between the normal and ferromagnetic layer would induce a precession of the magnetization in the ferromagnetic layer. Slonczewski (J. Magn. Magn. Mater. vol. 159, p. L1, 1996) has proposed a similar current-induced spin precession, as well as a switching of the magnetization between two different static directions. Tsoi et al. (Phys. Rev. Lett. vol. 80, p. 4281, 1998) have also obtained experimental evidence of such spin precession, in a Cu/Co multilayer traversed by a current normal to layers at 4 K. Recently, the inverse effect has been theoretically predicted by Berger and Slonczewski independently (L. Berger, Phys. Rev. B vol. 59, p. 11465, 1999). When an external microwave is absorbed under a ferromagnetic resonance (FMR) condition, precession of the magnetization will generate a DC voltage across the normal/ferromagnetic multilayer. In this work, we report the experimental results supporting such DC voltage generation.