Characterization of electrodeposited Co-W alloy thin films

The electrodeposition of the binary Co-W alloy films was investigated with different ratios of [WO42-]/[Co2+] in the citrate electrolyte at pH 4.0. X-ray diffraction (XRD) was employed to study the microstructure and phase composition of Co-W alloy thin films. The results showed that as-deposited Co-W alloy films were of crystalline, which converted from a Co-rich face-centred cubic (fee) phase to Co+Co7W6+Co3W coexisting when Co and W contents changed in the films. Compositional and morphological analysis of Co-W alloy films were obtained by the field-emission scanning electron-microscope (FE-SEM) equipped with EDX, indicating that Co-W alloy films were rich in cobalt. Moreover, tungsten contents increased with the ratios of [WO42-]/[Co2+] in solutions. The magnetic properties of Co-W alloy films were characterized using a vibrating sample magnetometer (VSM). The hysteresis loops suggested that the easily magnetized axis of Co-W alloy thin films was parallel to the surface of the films. A saturation magnetization of 131 A(.)m(2.)kg(.) and a coercivity of 3280 A(.)m(-1) were obtained when the current density was 1.0 A(.)dm(-2), and [WO42-]/[Co2+] was 0.15.