Abstract
The relation between the dry-etching time of the substrate and the magnetoresistance (MR) is discussed for Ni-Fe/Cu multilayers fabricated by a facing-targets sputtering method. The role of the underlying, Ta, Fe, Ni-Fe, or Ni-Fe fabricated in an N2 mixed sputtering atmosphere (Ni-Fe (N2)), is also discussed from the viewpoint of the relation between the microstructure and the GMR properties. Dry etching of the substrate surface with RF plasma before film deposition results in a remarkable increase in the MR ratio. An underlying 30-Å-thick Ta layer increased the MR ratio, while a 5-Å-thick Ni-Fe (N2) underlayer decreased it From an analysis of the structure and magnetic properties of the multilayers, it is concluded that enlargement of the grain diameter in the multilayers led to an enhancement of the interlayer magnetic coupling, and resulted in the remarkable increase in the MR ratio
