| Metallic nanomultilayers composed by magnetic material layer and nonmagnetic material layer arranged alternately and orderly, as one of nanostructure material, are characterized by perpendicular magnetic anisotropy energy and giant magnetoresistance. Because of above new properties, these materials have potential applications in making of high-powered magnetic field sensor, computer disks, CD-ROMs, magnetic head and so on.In this paper, Co/Pt, Co/Pd and Co/Cu nanomultilayers were prepared on the surface of Si(111) by methods of double-bath, double-pulse and continuous-flow single cell. The mechanism of electrochemical nucleation of Co,Cu,Pt,Pd was researched by polarization curve, potential step, REM, ECSTM, EQSM methods and so on. The structure and morphology of the multilayers were analyzed by SEM, XRD, AES. Meanwhile, the magnetic properties of multilayers were determined by magnetic hysteresis loops gotten by PPMS, and the correlation between structure and magnetic properties of nanomultilayers was also studied. Some of the main results are listed as follows:The growth process of Cu electrodeposition on the surface of Pt (111) in 0.5mol/L H2SO4 + 0.001mol/L CuSO4 solution was studied by ECSTM, REM and polarization curves. Experimental results showed that there were two stages of underpotential and bulk deposition in the electrodeposition of Cu on Pt (111). The growth of Cu layer on Pt exhibited layered growth at underpotential deposition stage, and three-dimensional (3D) nucleation growth at overpotential deposition stage. This result demonstrated that the growth mechanism of Cu deposition on Pt (111) surface accords with Stranski-Krastanov growth mechanism. The electrodeposition of Co on Pt (111) exhibits a 3D island growth mechanism at various deposition potentials in 0.05mol·L-1 H3BO3+0.01mol·L-1 CoSO4 solution. The nuclear number of Cu and Co in electrodeposition layer increased with the increase of overpotential. It could be observed from potential step method that the mechanism of the growth kinetics for Pt was 3D instantaneous nucleation at initial stage on the surface of single crystal Si (111) in H2PtCl6 and P salt solution whether the additive was added or not. At initial stage, the growth mechanism of Cu layer was proved to be 3D continuous nucleation in the basic bath,whereas the growth mechanism of Co layer was proved to be 3D continuous nucleation at low potential and 3D instantaneous nucleation at high potential in the basic bath. The growth mechanism of Cu layer, Co layer and Pd layer was proved to be 3D instantaneous nucleation at initial stage in plating solution with adding the additives. From the SEM images of Pd layer, the growth of nucleation could be decreased, the grains could be refined, and the electrodeposited film became level when the additives were added in plating solution. So the magnetic properties of the multilayer film could be improved greatly.Co/Pt, Co/Pd and Co/Cu nanomultilayers were successfully electrodeposited on the surface of Si (111) in boric acid solution by double-bath, double-pulse and continuous-flow single cell methods. And the technological conditions of electrodeposited process were optimized. The results of SEM and XRD indicated that the sublayers of the multilayer film were distinct and continuous, and had better periodical modulated structure. The compound of CoPt3 was first proved to exist in the boundary layer of Co-Pt, which is fcc structure. This result was not reported in the literature yet. The formation of CoPt3 was related to the potential and current density in the electrocrystallization.The magnetic hysteresis loop of multilayer film was tested by PPMS. The results showed that Co/Pt multilayers had perpendicular magnetic anisotropy and the easy-magnetization axis was perpendicular to the film face. It was found experimentally that coercive force was increased with increase of the Co-layer's thickness when film surface is perpendicular to magnetic field, but regardless of the Co-layer's thickness when film surface is in parallel with magnetic field. It was shown that coercive force of Co/Pd multilayers was increased with the decrease of Co-layer's thickness. The maximum value of coercive force reached 1130 Oe for the film obtained by double bath method and 1140 Oe for the film obtained by double-pulse method. The remanence ratio was greater than 0.8 for the film obtained by both methods. By adding In2O3 underlayer on the surface of Si(111), the coercive force of Co/Pd multilayers was up to 1840 Oe, and the value of the remanence ratio was 0.98. So the magnetic properties was best so far in multilayer film obtained by electorchemical method. The result shown the magnetic properties were greatly improved by In2O3 underlayer. The GMR value was increased and then decreased with the increase of Co-layer's thickness, and changed periodically with the increase of Cu-layer's thickness in Co/Cu multilayer film. With stacking number N increased, the GMR value was increased firstly and then decreased. The GMR value reached 90% when N increased to 60,while N was 80,the GMR value kept unchanged.
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