电沉积法制备Co-Pt合金薄膜的结构及其磁性能

Structure and magnetic properties of Co-Pt alloy thin films prepared by electrodeposition

采用酒石酸铵为络合剂,碱性溶液作为电解液沉积体系,利用电化学共沉积法在铜基底上制备得到了Co-Pt合金薄膜,并对制备得到的合金薄膜进行了不同温度的退火热处理。电化学极化曲线研究表明,酒石酸铵络合剂的加入有效地使两种金属离子沉积电位接近。原子吸收光谱研究表明,合金薄膜中金属成分比率易受电解液中金属离子比率和沉积电流密度的影响。X射线衍射(XRD)研究表明,电沉积制备得到的不同组分Co-Pt合金薄膜均为无序排列面心立方(fcc)结构,经过450℃退火热处理后部分转变为L10型超晶格结构。磁性研究表明,经过450℃退火热处理后的合金薄膜具有较好的磁晶各向异性。

Co-Pt alloy thin films have been successfully synthesized on a copper substrate by electrodeposition from an alkaline plating bath containing ammonium tartrate as complexing agent followed by subsequent annealing. Cathodic polarization curves showed that the difference between the deposition potentials of the two metal ions was reduced by the complexing action of the ammonium tartrate. Atomic absorption spectroscopy showed that the alloy composition can be readily controlled by adjusting the ratio of metal ions in the plating bath and the current density. X-ray diffraction showed that the as-deposited alloy films adopt a disordered face-centred cubic （fcc） structure. By annealing the alloy films at 450 ℃ the disordered phase structure partially transforms to the L10 ordered phase structure. Magnetic measurements showed that the L10 ordered Co-Pt alloy thin films exhibit high perpendicular coercivity.