Magnetic domain configuration in cobalt and permalloy micro-structures

We used atomic force microscopy to investigate the magnetic domain configurations in 65-nm-thick cobalt and permalloy rectangular micro-structures, in the virgin state, for various values of the aspect ratios. The two materials exhibited complex magnetic domain structures for lower aspect ratios, but exhibited single-domain structures for higher aspect ratios. In comparison with cobalt films, permalloy films showed much simpler domain structures and larger domain sizes. The domain sizes of cobalt and permalloy films were ∼ 1 μm and ∼ 2 μm, respectively, which were larger than those reported previously. This might have resulted from the large shape anisotropy of our samples.