Electrodeposition of Co-Cu-Zn/Cu multilayers:: influence of anomalous codeposition on the formation of ternary multilayers

Electrodeposited Co-Cu-Zn/Cu multilayers have been prepared with various control modes. It was found in all cases that the Zn content of the magnetic layer is higher than that in the corresponding dc-plated sample. The data of the composition analysis were elucidated by the assumption of anomalous codeposition of Zn and Co. When the less noble layer is deposited, a Zn-rich zone is produced first, then it is covered with a Co-rich layer. If exchange reaction was allowed during the pulse-plating, Co dissolved selectively while the Zn content of the Co-rich layer remained unchanged. The relative resistance of Zn against the exchange reaction is due to the limited accessibility of the Zn-rich zone of the sample rather than electrochemical reasons. The structure of the deposit was analyzed by X-ray diffraction (XRD). It was revealed that Zn incorporation leads to strongly textured deposits with (111) orientation. The Zn atoms also enlarge the lattice distances of all phases formed. The incorporation of Zn into the magnetic layer of the multilayers decreases the magnetoresistance of the samples. (C) 2004 Elsevier Ltd. All rights reserved.