CoPtW thin films prepared by magnetic electroplating

Abstract

CoPtW alloy films were prepared by magnetic electrodeposition method to replace conventional sputtering on copper substrate. The effects of different H₂PtCl₆ concentrations and magnetic intensities on the composition, microstructure and magnetic properties of CoPtW alloy films were investigated. With the increasing H₂PtCl₆ concentration, the amounts of Pt in CoPtW films increased dramatically, but the contents of both Co and W reduced gradually. Almost all of the deposited films were crystalline and contained CoPt(111), CoPt(002) and Co(002) peaks. The strongest perpendicular magnetic anisotropy could be observed when the H₂PtCl₆ concentration was up to 0·02 mol L⁻¹. A higher H₂PtCl₆ concentration would result in bigger and agglomerate nodular structures with lots of pores. The magnetic field parallel to the electrodes during the electrodeposition process could improve the deposition rate and increase the amounts of Co in CoPtW alloy films. Magnetic fields would induce cobalt growing along the (002) orientation. Films of smaller grain size and smooth surface could be formed under high magnetic intensity (0·8 T) as a result of magnetic force and magnetohydrodynamic effects. Moreover, a transition process from hard magnetism to soft magnetism could be observed when the magnetic intensity increased from 0 to 0·8 T.

Keywords:

• CoPtW alloy film
• Magnetic electrodeposition
• Magnetism

This work was supported financially by the Natural Science Foundation of ZheJiang Province (grant no. Y4110290) and the National Natural Science Foundation of China (grant no. 20971116).