Electrochemical fabrication of multi-nanolayers

The fabrication of multi-nanolayer structures can in some cases be achieved electrochemically if, for example, the plating current density has a significant effect on the deposit composition or if reverse plating changes the composition. Moreover, the realization of a multi-nanolayer structure can also crucially affect the properties of the material. This chapter will look at one material system in which both of the above apply, namely, amorphous Co-P. When produced using conventional DC plating, amorphous Co-P tends to exhibit perpendicular magnetic anisotropy and hence very low permeability and somewhat high coercivity. This limits the usefulness of the material as a magnetic core for power conversion applications which require low coercivity, high saturation magnetization, high permeability, high anisotropy field, and high resistivity. Riveiro et al. used pulse reverse plating to fabricate multilayers of alternate magnetic and nonmagnetic materials. With the thickness of the magnetic layers at around 30 nm, they were able to achieve in-plane anisotropy and low coercivity 8 A m^-1. This chapter will describe the early work and a selection of subsequent research on multi-nanolayers of amorphous Co-P, e.g., Perez et al., who used pulse plating, and McCloskey et al., who improved the saturation magnetization and thermal stability of the material.