Structural and Magnetic Properties of Electrodeposited Cobalt-Polypyrrole Composite Films

Abstract

Co particles were electrodeposited at an electrode potential of -2.0 V on ITO/PPy (500 nm) substrates. During Co electrodeposition, charge density was changed from 400 to 5000 mC cm-2 in order to control the Co amount. Current density-time transients showed that the dominant reaction is PPy undoping for the initial times and Co deposition for the later times. Structural characterization was done by a Fourier transformed infrared (FTIR) spectrometer and a scanning electron microscope (SEM). FTIR spectra of the Co-PPy composite films have similar to that of the PPy film but peak intensities decrease as the charge density increases due to the surface covering by Co (by SEM). The chemical composition was detected by an energy dispersive spectrometer. For all films, C and N (belonging to PPy layer), O (due to oxidized character of PPy layer), F (doping anion) and Co peaks were obtained. Magnetic properties were measured by a vibrating sample magnetometer. Some films with Co charge density of 600, 700, 4000 and 5000 mC cm-2 have nearly isotropic magnetic behavior and the others are anisotropic. The isotropic behavior may arise from the very weak texture and preferred orientation of the films.