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The Contribution of Domain‐Wall Oscillations to the Small‐Signal Permittivity of Triglycine Sulphate
Author(s) -
Fousek J.,
Janoušek V.
Publication year - 1966
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.19660130118
Subject(s) - permittivity , ferroelectricity , condensed matter physics , triglycine sulfate , polarization (electrochemistry) , debye , crystal (programming language) , low frequency , frequency domain , materials science , single crystal , signal (programming language) , dielectric , physics , nuclear magnetic resonance , chemistry , mathematics , mathematical analysis , optoelectronics , astronomy , computer science , programming language
The complex permittivity ϵ * of ferroelectric triglycine sulphate is measured in a weak ac field in the frequency range 5 × 10 2 to 5 × 10 7 Hz as a function of the net polarization P a of the sample. The value of P a is adjusted in steps by charge supplied from a parallel capacitor. Throughout the frequency range both components of ϵ * are larger for crystals with | P a |≠| P s | than for a single‐domain crystal with | P a | = | P s |. This indicates a contribution Δϵ w * to the permittivity by the domain walls. The imaginary component Δϵ w ″ is an order of magnitude greater than the value of ϵ″ of a singel‐domain crystal; Δϵ w ′ is up to five times larger than the ϵ′ of a single‐domain crystal. The frequency dependence of Δ w * suggests contributions from two different mechanisms. The frequency dependence of one of them is given approximately by the Debye equations with τ ≈ 10 −7 s. Both components of the second contribution to Δϵ w * decrease monotonically with frequency. The probable mechanisms of these contributions are discussed.