Relation between magnetoresistance and nanostructure of current-perpendicular-to-plane giant-magnetoresistance film with current-confined-path nano-oxide layer

Nanostructure of a current-perpendicular-to-plane giant-magnetoresistance film with a current-confined-path (CCP) nano-oxide layer was analyzed by high-resolution transmission electron microscopy and three-dimensional atom probe. It was found that the CCP of a film with a higher magnetoresistance (MR) ratio has better crystalline orientation and higher purity than the CCP of a film with a smaller MR ratio. Moreover, the free layer on the CCP of a film with a high MR ratio is well crystallized. Both the CCP with the good crystalline orientation and high purity and the well-crystallized free layer diminish the diffusive electron scattering, which improves an MR ratio.