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Broadband ferromagnetic resonance responses for metallic single-layer and bilayer magnetic films with total thicknesses smaller than the microwave magnetic skin depth have been studied. Two different types of microwave stripline transducers were used to excite and detect magnetization precession: a coplanar waveguide and a microstrip line both with characteristic width larger than the free propagation path for traveling spin waves along the film. Both transducers show efficient excitation of higher-order standing spin wave modes across the film thickness in samples 30-91 nm thick. The ratio of amplitudes of the first standing spin wave to the fundamental resonant mode is independent of frequency for single-layer permalloy films. In contrast, we find a strong variation in the amplitudes with frequency for cobalt-Permalloy bilayers and the ratio is strongly dependent on the ordering of layers with respect to a stripline transducer. Most importantly, cavity ferromagnetic resonance measurements on the same samples show considerably weaker amplitudes for the standing spin waves. All experimental data are consistent with expected effects of eddy currents in films with thicknesses below the microwave magnetic skin depth. Finally, conditions for observing eddy current effects in different types of experiments are critically examined. [ABSTRACT FROM AUTHOR]

Tunneling magnetoresistance spectroscopy measurements have been performed on spin-valve magnetic tunnel junctions where the free magnetic electrode is a Cu38Ni62 alloy with a Curie temperature of around 240 K. These measurements allow us to follow the temperature dependence of the energy of the bottom of a minority-spin band close to the Fermi energy, which is partly responsible for the tunneling conductance. The temperature dependence of the tunneling spin polarization of the CuNi electrode has also been extracted using the Julliere formula. We show that the tunneling spin polarization as a function of temperature can be related to the temperature-dependent magnetization using an extension of the commonly applied Stearns model that incorporates the motion of the band close to the Fermi level. This model reproduces the nonlinear relation between tunneling spin polarization and magnetization obtained for Cu38Ni62. [ABSTRACT FROM AUTHOR]

Electron scattering mechanisms within metallic multilayers are affected by both structural and magnetic disorders. Off-specular x-ray scattering has long been used to probe the structural interfaces, and it is only recently that it has been applied to the study of magnetic disorder. We compare the resonant magnetic x-ray scattering with off-specular neutron studies from magnetron-sputtered Co/Cu and Co/Ru multilayers grown at the second antiferromagnetic coupling peak. Both techniques yield similar results for the Cu system, and a simple domain model can be applied to extract the magnetic interface morphological parameters. For the Cu system, the in-plane correlation length is field dependent and is 880 ± 20 Å after saturation along the hard axis, but increases to 7000 ± 100 Å after saturation along the orthogonal easy axis. Both systems show strong out-of-plane correlations in both the structural and magnetic disorders. In all cases, the out-of-plane correlation length for the structural interfaces is 200-250 Å, but the ratio of the magnetic to structural correlations length is dependent on the magnitude of the exchange coupling and ranges from 0.4 to 1.4. [ABSTRACT FROM AUTHOR]