THE EFFECT OF PRECESSION OF MAGNETIZATION VECTOR ON THE MÖSSBAUER SPECTRA OF SUPERPARAMAGNETIC PARTICLES

Institute of Chemistry, Leningrad State university, Leningrad 199164, U.S.S.R.

Abstract

It is shown, that the description of the time development of the magnetic moment of superparamagnetic particles in terms of the dis crete orientations model is the main reason of the distinction between the theoretical and experimental spectra. The model of the time development of magnetic moment which takes into account the jumps from one easy direction to another as weIl as the precession at the time between the jumps, gives a reasonable explanation for the broadening and the asymmetry of the experimental lines.

Résumé

On montre que l'évolution en fonction du temps du moment magnétique de particules superparamagnétiques, dans un modèle d'orientations discrètes, est la raison principale du désaccord entre les spectres théoriques et expérimentaux. On obtient ainsi une explication raisonnable de l'élargissement et de l'assymétrie des raies expérimentales.