Nickel concentration dependent evolution of magnetic domain structures in electrodeposited carbon composite thin films

Abstract

Modification of magnetic domain structure of Ni-C composite thin films has been investigated with the variation in nickel content in the films. Ni-C thin films were synthesized by electrodeposition method with different nickel molar concentration in the electrolyte. Compositional analysis of the films performed by EPMA mapping assured nearly homogeneous distribution of nickel and carbon in the films at a scale much larger than the crystallographic features within the films. GIXRD and TEM studies reveal the presence of crystalline phase of nickel along with diamond and graphite phases within amorphous carbon. Morphological properties studied by AFM showed granular features with variation in roughness. Within amorphous carbon matrix of the films, presence of sp3 and sp2 phases (Ni-DLC) were confirmed by Raman spectroscopy in low nickel content thin films. Stripe magnetic domain structures of varying width and density were observed in the films with change in nickel content without application of external magnetic field at room temperature by magnetic force microscopy. Ni-DLC thin films exhibit the highest domain density of all Ni-C composite thin films.