In-situ magnetoresistance measurements on spin valve elements combined with Lorentz transmission electron microscopy

In order to correlate giant magnetoresistance with changes in magnetic domain structure, we have studied lithographically-defined spin-valve elements in-situ by Lorentz transmission electron microscopy, whilst simultaneously passing a controlled current through the clement and applying a magnetic field. For a given current, the changes in magnetic domain structure can thus be correlated with changes in the resistance of the film. Spin valve structures with MnFe and MnNi pinning layers were examined and the technique proved particularly useful in identifying regions of the spin valve corrupted by corrosion of the pinning layer.