Prodding the Magnetic Properties of Sono-Electrodeposited Nickel by Magnetic Force Microscope (MFM)

Abstract

Nickel is a ferromagnetic material. These materials have some unpaired electrons, so their atoms have a net magnetic moment. They get their strong magnetic properties due to the presence of magnetic domains. Electrodeposited Ni has been used in Integrated circuits, service apparatus and functionally suitable metal coating. In this study, Ni is potentiostatically electrodeposited both in presence (sonication) and absence (silent) of ultrasound. The use of ultrasound irradiation during the deposition generates a specific agitation resulting from the cavitation phenomena and can possibly alter the mechanism and kinetics of phase formation. Crystalline graphite substrate is chosen for the study because of the lower nucleation rate on carbon compared with metallic electrodes. Thus the overlap of the nuclei can be delayed and hence the morphology of the nuclei can be fairly distinct. The conventional Watt’s bath is chosen for the electroplating, with a modification in the deposition temperature i. e. at 25 °C instead of 60 °C. In both cases the high crystallinity are confirmed by x-ray diffraction. The morphological analysis is performed by scanning electron microscopy and atomic force microscopy. In both the cases a good surface coverage of agglomerated grains of 100-150 nm are observed. However, sonicated samples are coarser than the silent. By using magnetic force microscopy, the distribution of magnetic domains with the morphology gives an insight into the phase formation mechanism. The silent Ni deposit has repulsive type single magnetic domain parallel to the surface, whereas the sonicated sample has both attractive and repulsive single as well as multiple domains. This could be attributed to the variation of morphology in both the conditions. Our current understanding to these mechanistic descriptions to the behavior will need more accurate measurement in order to provide a detailed understanding.