INFLUENCE OF STRONG MAGNETIC FIELDS ON FERROELECTRIC PHASE TRANSITIONS

The ferroelectric soft mode in SbSI has been investigated by Raman scattering in strong magnetic fields up to 14 Tesla. The mode frequency shifts towards lower frequencies for a magnetic field perpendicular to the ferroelectric c-axis while the mode frequency is unaffected for a field oriented parallel to the c-axis The effect is explained in terms of a recent theoretical model which is based on the anomalously strong electron-phonon coupling of the 3p electrons located at the sulphur ions.