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We have performed in situ transport measurements on CoFeB/AlO/Co spin-valve magnetic tunnel junctions during annealing up to 200 °C. For optimally oxidized junctions we observe a marked decrease in the parallel state junction resistance, which occurs at around 150 °C and continues throughout the anneal process until the temperature is reduced back below 150 °C. Spectroscopic measurements reveal a stronger bias dependence due to enhanced magnon-assisted tunneling, and show that features relating to weak fcc texture in the cobalt upper electrode fade after annealing at 200 °C. We attribute this to a possible amorphization of the cobalt electrode in close proximity to the barrier interface. [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]

The observed magnetotransport properties of magnetically coupled multilayers depends not only on the nature of the magnetic coupling but also the magnetic domain correlations and disorder. Neutron scattering gives access to the magnetic coupling through the specular reflectivity and the domain correlations through the diffuse scattering. Sputtered multilayers of Co/Cu and Co/Ru have been investigated as a function of the applied magnetic field. A simple domain model relates the observed scattering to the domain correlation length and the magnetic disorder. In both systems highly vertically correlated magnetic domains are observed with in-plane correlation lengths, at remanence, of 1.5 and 7 μm for the Cu and Ru systems, respectively. In both systems the Co domains order antiferromagnetically across the nonmagnetic spacer. The remanent vertically correlated state is recovered after saturating the sample. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]