It was reported previously [Trans. Inst. Met. Finish. 85, 94 (2007)] that during potentiostatic electrodeposition from electrolytes containing a low concentration of Co2+ and Mn2+ ions and boric acid, a layered structure consisting of alternating Co-rich and Mn-O-B-rich zones can be formed. In the present study, electrodeposition was carried out from both sulfamate and sulfate electrolytes. A cyclic voltammetry study was performed for identifying the potential intervals associated with the deposition regimes of the components. The current amplitude data recorded during electrodeposition exhibited a periodic oscillation with a period of 1.9 ± 0.1 s. The fast Fourier transforms of the chronoamperometric data showed two maxima, the ~0.5 Hz peak corresponding to the major oscillation period and the ~1 Hz peak to the first harmonic one. An analysis of the overall deposit composition revealed that the Mn/Co ratio was typically in the range from about 0.05 to 0.25, the sulfamate bath resulting in systematically higher values. The X-ray diffraction patterns of the deposits were dominated by a broad Gaussian peak characteristic of an amorphous phase. The room-temperature magnetization indicated that the deposits contain nanometer-sized magnetic entities with superparamagnetic behavior.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry