Raman measurements of the ferroelectric ba_0.4Sr_0.6Nb₂O₆

Using Raman spectroscopy, we have measured the A1 (TO) and E(TO) phonons in the tungsten bronze structured ferroelectric Ba0.4Sr0.6Nb2O6 (BSN). We observe phonon anomalies associated with Tc and also with a temperature ≈425°C. The latter is in the region where index of refraction measurements indicate the onset of a local polarization. By quenching the crystal from high temperatures, Tccan be shifted. We find that the phonon anomalies shift corresponding to the new Tc values. © 1990, Taylor & Francis Group, LLC. All rights reserved.