Raman spectroscopic study of the size-dependent order parameter of barium titanate
Abstract
Spherical barium titanate nanoparticles, having a diameter of 50–500 nm, were characterized using micro-Raman spectroscopy at 83 K. Proposed is a calibrated intensity method allowing a spectroscopic estimate of the relative fraction of two solid-state structural phases, where the phases have uniquely identifiable Raman bands. The Raman spectroscopy local probe is broadened to quantify macroscopic characteristics, such as the order parameter. Based on the intensity of the 311 cm−1 mode, it is revealed that the order parameter, η, of BaTiO3 decreases exponentially with particle size reduction. Similarly, an exponential decrease of the long-range (dipole-dipole) interaction is suggested, based on the Raman shift of the 716 cm−1 mode. An approximate long-range interaction decrease of 3% is estimated when the particle size is reduced from 500 nm to 50 nm. This study provides evidence that BaTiO3 nanoparticles can be modeled as being composed of coexisting cubic and non-cubic phases with relative fraction controlled by the degree of long-range Coulombic interactions.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 02, 2014
- Source ID
- 10.1063/1.4880996
Entities
People
- Brian D. Hosterman
- Mariana Sendova
Organizations
- New College of Florida
- United States Army Research Laboratory