Co-Ni合金薄膜的电化学外延及同步辐射XMCD研究

Electrochemical Epitaxy and XMCD Study of Co-Ni Alloy Film

采用电化学循环伏安法在单晶GaAs(001)衬底上外延沉积了Co-Ni二元合金薄膜.扫描电子显微镜观察结果显示,薄膜厚度约180nm,其表面由约40nm大小的颗粒组成.用X射线荧光法确定了薄膜的组分为Co66Ni34,XRD确定了其为面心立方结构.用同步辐射圆偏振软X射线分别测量了样品中Co和Ni的吸收谱(XAS),从而得到X射线磁性圆二色(XMCD)谱,通过加和定则分别计算出了合金中Co和Ni的轨道磁矩和自旋磁矩,与纯的Co和Ni样品相比,它们都有不同程度的增加.

Using the electrochemical cyclic voltammetry, Co-Ni alloy film was deposited on single crystal GaAs （001） substrate. With the scanning electron microscopy （SEM） and X-ray fluorescence （XRF）, the thickness of the film was about 180 nm and the surface of the alloy was composed of 40 nm-sized Co66Ni34 nanograins. The faced center cubic structure of the alloy was confirmed using X-ray diffraction （XRD）. The X-ray magnetic circular dichroism （XMCD） spectra of Co and Ni were obtained from the X-ray absorption spectra （XAS） results using synchrotron radiation circularly polarized soft X-ray. According to the sum rules, the orbital and the spin magnetic moments of Co and Ni were separately obtained. Compared with the pure Co and Ni samples, the orbital and the spin magnetic moments of Co and Ni in the epitaxial Co-Ni alloy showed an increase to some extent.