Optical and ferroelectric properties of lead titanate nanocrystals dispersed within borate glass matrix

Lead titanate nanocrystals dispersed within the borate glass matrix (composite) with the composition 75 B2O3-25 PbTiO3 (in mol %) was prepared. The composite's XRD analysis indicated it contains glassy phase, and this was further confirmed by DSC study. TEM, SAED, and FTIR analyses provided evidence that the PbTiO3 nanocrystals dispersed within the borate glass matrix, establishing the composite nature of this sample. The average particle size found of PbTiO3 was determined to be 57.2 nm via TEM. The composite's FTIR analysis indicated the presence of BO3 with NBO's, and BO4 units. Additionally, the presence of the Ti3+ ions in TiO6 units as well as Ti4+ ions in TiO4 and TiO6 units. The Curie temperature (Tc) of PbTiO3 in present composite sample was confirmed through both DSC and dielectric studies. Optical analysis of this composite sample unveiled three transmission bands, one corresponding to the 3Γ5 →2Γ3 charge transfer transition between Ti3+ and Ti4+ions. While the other transitions 2B2g →2B1g and 2B2g →2A1g are corresponding to the octahedral of Ti3+ (3d1) ions in tetragonal distorted sites. The polarization-field (P-E) loops of this composite sample at various electric fields unveiled relatively narrow hysteresis loops.