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Dielectric dispersion of ferroelectric ceramics and single crystals at microwave frequencies
Author(s) -
Arlt G.,
Böttger U.,
Witte S.
Publication year - 1994
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.19945060703
Subject(s) - materials science , condensed matter physics , ferroelectricity , dielectric , microwave , piezoelectricity , debye , ceramic , physics , composite material , optoelectronics , quantum mechanics
The dielectric constant of ferroelectric ceramics shows strong Debye‐like relaxation at GHz frequencies. This relaxation is caused by sound generation inside the crystallites. The ferroelastic domain walls which vibrate in the electric ac field are very effective shear wave transducers. The shear wave emission has a maximum when the wavelength of the sound wave is comparable to the width of the domains. Above this frequency the domain walls can no longer vibrate due to inertia and do not contribute to the dielectric constant. The observed dependence of the microwave dispersion on temperature, doping and grain size of the ferroelectric ceramic is in good agreement with the proposed mechanism of the emission of acoustic shear waves.