# Analytical description of the size effect on pyroelectric and electrocaloric properties of ferroelectric nanoparticles

## TL;DR

This paper analytically investigates how the size of ferroelectric nanoparticles influences their pyroelectric and electrocaloric properties, providing insights for optimizing energy conversion and cooling applications.

## Contribution

It introduces an analytical model linking nanoparticle size to pyroelectric and electrocaloric effects, enabling targeted design of ferroelectric nanocomposites.

## Key findings

- Maxima of pyroelectric and electrocaloric coefficients can be induced by size changes.
- Size controls the width, height, and sign of the effects.
- Analytical expressions help optimize nanoparticle parameters for applications.

## Abstract

Using Landau-Ginzburg-Devonshire theory and effective medium approximation, we analytically calculate typical dependences of the pyroelectric and electrocaloric coefficients on external electric field, temperature and radius for spherical single-domain ferroelectric nanoparticles. The considered physical model corresponds to the nanocomposite with small fraction of ferroelectric nanoparticles. Within the framework of the analytical model we establish how the size changes determine the temperature and field behavior pyroelectric and electrocaloric coefficients on example of BaTiO3 nanoparticles covered by a semiconducting shell and placed in a dielectric polymer. We show that by changing the particle size one can induce maxima of the pyroelectric coefficient and electrocaloric temperature variation, control their width, height and sign. Obtained analytical expressions allow selecting the interval of particle sizes, voltage, and/or temperature for which pyroelectric energy conversion and electrocaloric coefficient are optimal for applications. The observed size effect opens the possibility to control pyroelectric and electrocaloric properties of ferroelectric nanocomposites that can be important for their advanced applications in energy convertors and cooling systems.

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Source: https://tomesphere.com/paper/1906.02953