Study of relaxation effects in the 57Fe Mössbauer spectra of carbon-supported iron carbide particles

Abstract
A modified model of relaxation for systems containing both a magnetic field and an electric field gradient is presented. This model is used to explain the 57Fe Mössbauer spectra of small iron χ‐carbide particles supported on two types of high surface area carbon. On the basis of this model, it is concluded that χ‐carbide particles interact weakly with graphitic carbon, but very strongly with nearly amorphous carbon. On the nearly amorphous carbon, the particles may, in fact, have an unusually high surface‐to‐volume ratio.