Discovery of Strange Kinetics in Bulk Material: Correlated Dipoles in CaCu3Ti4O12

Abstract

Dielectric spectroscopy of CaCu3Ti4O12 was performed spanning broad ranges of temperature (10-300K) and frequency (0.5Hz-2MHz). We attribute the permittivity step-fall to the evolution of Kirkwood-Fröehlich dipole-correlations; reducing the moment-density due to anti-parallel orienting dipoles, with decreasing temperature. Unambiguous sub-Arrhenic dispersion of the associated loss-peak reveals the prime role of strange kinetics; used to describe nonlinearity-governed meso-confined/fractal systems, witnessed here for the first time in a bulk material. Effective energy-scale is seen to follow thermal evolution of the moment density, and the maidenly estimated correlation-length achieves mesoscopic scale below 100K. Temperature dependence of correlations reveals emergence of a new, parallel-dipole-orientation branch below 85K. Novel features observed define a crossover temperature window connecting the single-dipoles regime and the correlated moments. Conciling known results, we suggest a fractal-like self-similar configuration of Ca/Cu-rich sub-phases; resultant heterogeneity endowing CaCu3Ti4O12 its peculiar electrical behaviour.

arXiv comment19 pages, 5 figures, 44 references

References in corpus (5)

• Non-intrinsic origin of the Colossal Dielectric Constants in CaCu3Ti4O12
• Relaxor ferroelectricity and colossal magnetocapacitive coupling in ferromagnetic CdCr2S4
• Antiferromagnetism in CaCu${}_3$Ti${}_4$O${}_{12}$ studied by magnetic Raman spectroscopy
• Relaxation dynamics and colossal magnetocapacitive effect in CdCr2S4
• Fractional Power-Law Spectral Response of CaCu3Ti4O12 Dielectric: Many-Body Effects

Cited by in corpus (1)

• Copper Titanates: A Family of Magneto-Quantum Paraelectrics