Electrochemical deposition and modification of Cu/Co-Cu multilayer

Multilayers of Cu/Co-Cu were electrodeposited from a citrate electrolyte on quartz with Au and Si substrates with a Permalloy/Cu seedlayer by means of the potentiostatic double-pulse technique simultaneously controlled by microgravimetric measurements. The influence of a superimposed magnetic field and of annealing conditions on the microstructure has been studied. When an external magnetic field is parallel-orientated toward the electrode, an increase of the Cu deposition rate was observed due to magnetohydrodynamic effects. In contrast, the deposition rate of Co decreases. Microstructural investigations have shown that both a superimposed uniform magnetic field up to 600 mT and an inhomogeneous field of an SmCo permanent magnet change the microstructure and improve the GMR effect. X-ray diffraction measurements revealed that all grains are arranged in the <1 1 1> direction in contrast to layers formed without magnetic field with only 75% of the grains having a (1 1 1) texture. Isothermal heat treatment at different temperatures increases the GMR effect corresponding to an increase of grain size with preferred (1 1 1) orientation