| 摘要 |
Highly coercive (out-of-plane) hard magnetic films of cobalt-platinum-phosphorus (CoPtP) composition doped with tungsten (W) were fabricated by direct current (DC) galvanostatic electrodeposition. With the addition of 0.003 mol/L of W in the electrolyte solution for CoPtP, coercivity (Hc) of about 3664-3784 Oe, absolute remanent magnetization (Mr) of 7.8-8.4 memu, and squareness (S) of about 0.53-0.55 were achieved for electroplated CoPtWP single-layered film. Upon annealing in ambient atmosphere at 320° C. for 2 hrs, an improvement in magnetic property was observed with Hc of about 4211-4619 Oe, an absolute Mr of about 7.0-8.4 memu, and a S of about 0.68-0.85. Annealing in air caused oxidation of the CoPtWP leading to a slight decrease in absolute Ms and Mr but a marked improvement in Hc and S due to the presence of non-magnetic metallic oxides formed at the grain boundaries. To achieve higher absolute magnetization, CoPtWP/Au multilayered structures were fabricated by a stepwise plating process. In comparison to a single layered film, a 3-layered structure exhibited a higher absolute Mr of about 14.9 memu, Hc of about 3927 Oe with S about 0.58 after annealing at 320° C. for 3 hrs via a separate annealing sequence.
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