Space-charge mechanism of aging in ferroelectrics: an exactly solvable two-dimensional model

Abstract

A mechanism of point defect migration triggered by local depolarization fields is shown to explain some still inexplicable features of aging in acceptor doped ferroelectrics. A drift-diffusion model of the coupled charged defect transport and electrostatic field relaxation within a two-dimensional domain configuration is treated numerically and analytically. Numerical results are given for the emerging internal bias field of about 1 kV/mm which levels off at dopant concentrations well below 1 mol%; the fact, long ago known experimentally but still not explained. For higher defect concentrations a closed solution of the model equations in the drift approximation as well as an explicit formula for the internal bias field is derived revealing the plausible time, temperature and concentration dependencies of aging. The results are compared to those due to the mechanism of orientational reordering of defect dipoles.

arXiv comment8 pages, 4 figures. accepted to Physical Review B

References in corpus (3)

• Physics of thin-film ferroelectric oxides
• Hardening-softening transition in Fe-doped Pb(Zr,Ti)O3 ceramics and evolution of the third harmonic of the polarization response
• Drift of charged defects in local fields as aging mechanism in ferroelectrics

Cited by in corpus (6)

• Charge migration in Pb(Zr,Ti)O3 ceramics and its relation to ageing, hardening and softening
• Aging of poled ferroelectric ceramics due to relaxation of random depolarization fields by space-charge accumulation near grain boundaries
• Surface potential at a ferroelectric grain due to asymmetric screening of depolarization fields
• Depletion layer-induced size effects in ferroelectric thin films: A Ginzburg-Landau model study
• Elastic aging from coexistence and transformations of ferroelectric and antiferroelectric states in PZT
• Influence of space charge on domain patterns and susceptibility in a rhombohedral ferroelectric film