Anisotropic Damping in Single-Crystalline Ni/MgO(001) studied by the Time-Resolved Magneto-Optical Kerr effect (TR-MOKE)
Abstract
The damping behavior of uniform spin precession in single- crystalline Ni/MgO(001) of various thicknesses from t = 10 nm to t = 60 nm is investigated in the time domain using TR-MOKE over a wide range of external field parameters and temperatures. Planar measurements indicate that the effective Gilbert damping parameter, αeff, is coupled to the magnetocrystalline anisotropy, as αeff ranges from 0.05 near the hard axis to 0.10 near the easy axis. Previous experiments by other groups using FMR [1] and TR-MOKE on polycrystalline samples [2] have placed the intrinsic value of the damping at 0.045. When the field is applied normal to the film surface, αeff increases to as high as 0.3 when the angle of the magnetization, φM, is greater than 45 degrees out of plane. These results are discussed in terms of various models of extrinsic damping mechanisms, such as two magnon scattering. [1] S. Bhagat et al. Phys. Rev. B, 10 179 (1974) [2] J. Walwoski et al. J. Phys. D: Appl. Phys. 41 164016 (2008)
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2009
- Bibcode:
- 2009APS..MART32001S