Fractional Power-Law Spectral Response of CaCu3Ti4O12 Dielectric: Many-Body Effects

TL;DR

This study reveals that the dielectric response of CaCu3Ti4O12 exhibits fractional power-law behavior due to many-body dipole interactions, with temperature-dependent dynamics indicating a transition from collective to single-particle relaxation.

Contribution

It demonstrates that the dielectric spectral response is governed by many-body effects and fractal configurations, confirmed through spectral fitting to Dissado-Hill behavior, highlighting temperature-dependent relaxation dynamics.

Findings

Spectral response shows fractional power-law behavior.

Temperature influences the relaxation from collective to single-particle.

Spectral fits confirm many-body dipole-interactions.

Abstract

Spectral character of dielectric response in CaCu3Ti4O12 across 0.5Hz-4MHz over 45-200K corresponding to neither the Debyean nor the KWW relaxation patterns rather indicates a random-walk like diffusive dynamics of moments. Non-linear relaxation here is due to the many body dipole-interactions, as confirmed by spectral-fits of our measured permittivity to the Dissado-Hill behaviour. Fractional power-laws observed in {\epsilon}*({\omega}) macroscopically reflect the fractal microscopic configurations. Below ~100K, the power-law exponent m (n) steeply decreases (increases), indicating finite length-scale collective response of moment-bearing entities. At higher temperatures, m gradually approaches 1 and n falls to low values, reflecting tendency towards the single-particle/Debyean relaxation.