MOSSBAUER STUDY OF BROWNIAN-MOTION OF FESNO3 PARTICLES IN LIQUID-CRYSTAL N-(PARA-ETHOXYBENZYLIDENE)-PARA'-BUTYLANILINE (EBBA)

The effects of Brownian motion of small particles of FeSnO3 in liquid-crystal EBBA on 14.4-keV Fe57 and 23.8-keV Sn119 Mössbauer spectra in the temperature range 300 - 360 K are reported. Mössbauer spectral lines begin to broaden a few degrees below the solid nematic phase-transition temperature. In the nematic range and in the isotropic liquid region, except very close to the nematic isotropic phase-transition temperature, the line broadening (E-) is linearly proportional to T. There is an anomalous change in the line broadening at and near the nematic isotropic phase-transition temperature. The area under resonance sharply decreases at the solid nematic phase transition. In the nematic and in the isotropic region, line broadening is associated with decrease in recoilless fraction. © 1979 The American Physical Society.