Pyroelectric behavior and dielectric properties of linear copolysiloxane/eicosylamine superlattice
Material Science Laboratory, Physics Department, University of Malaya, 50603 Kuala Lumpur, Malaysia
Corresponding author: a email@example.com
Revised: 30 December 2004
Published online: 16 June 2005
The pyroelectric behavior and dielectric properties of a superlattice containing a Langmuir-Blodgett (LB) film of alternately monomeric eicosylamine and linear copolysiloxane substituted with aromatic acid side chains have been investigated in the temperature range of 13 - 29 °C. The pyroelectric coefficient of the superlattice increases with temperature, exhibiting the highest coefficient of 6.2 ± 0.2 µcm-2K-1 at 29 °C. The dielectric behavior of the superlattice is investigated by examining the dielectric loss and capacitance in the frequency range of 102 to 105 Hz. The maximum loss values for all temperatures in the range occur at a frequency ~5000 Hz which correspond to a relaxation time of 3.18 × 10-5 s. The Cole-Cole plots obtained experimentally are found to be broad and fall inside the semicircle derived from the Debye relaxation theory. However, they agree fit with the semi-empirical Cole-Cole relaxation model. The parameter α obtained from the Cole-Cole relaxation model decreases with temperature indicating the rise in the internal degrees of freedom of the dipole in the superlattice.
PACS: 77.22.-d – Dielectric properties of solids and liquids / 77.70.+a – Pyroelectric and electrocaloric effects
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005