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Updated: Jun 20, 2026
06:54
Characterization of Nanocrystal Size Distribution using Raman Spectroscopy with a Multi-particle Phonon Confinement Model
Published on: August 22, 2015
The negative phonon confinement effect in nanoscopic sodium nitrite.
E Yu Koroleva1, D Nuzhnyy, J Pokorny
1Ioffe Institute, 26 Politekhnicheskaya, 194021 St-Petersburg, Russia. e.yu.koroleva@mail.ioffe.ru
Nanotechnology
|September 3, 2009
Summary
This study investigated a porous glass and sodium nitrite (NaNO2) ferroelectric nanocomposite. Local depolarization fields at interfaces, not size effects, influence its ferroelectric properties.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Ferroelectric materials exhibit spontaneous electric polarization.
- Nanocomposites offer unique properties by combining different materials.
- Understanding ferroelectricity in confined systems is crucial for device applications.
Purpose of the Study:
- To investigate the ferroelectric properties of a porous glass/sodium nitrite (NaNO2) nanocomposite.
- To analyze the influence of nanoscale confinement on ferroelectric behavior.
- To determine the role of interfaces and size effects on the material's dielectric function.
Main Methods:
- Infrared reflectivity and THz transmission spectroscopy were used to study the nanocomposite.
- Raman spectroscopy was employed to analyze phonon modes.
- Temperature-dependent measurements were conducted from 300-500 K, covering the ferroelectric transition.
- Effective medium models (Bruggeman, Lichtenecker) were used for comparison.
Main Results:
- The effective dielectric function showed good qualitative agreement with effective medium models.
- Stiffening of effective modes was attributed to local depolarization fields at glass-ferroelectric interfaces.
- Nonpolar Raman modes of NaNO2 showed minimal changes compared to bulk.
- Signatures of the ferroelectric transition were observed within the nanocomposite.
Conclusions:
- Intrinsic size effects, such as phonon confinement, are negligible in this specific nanocomposite.
- Local depolarization fields at the interfaces play a significant role in the observed ferroelectric behavior.
- The study provides insights into the physics of ferroelectricity in nanoconfined systems.
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