Correlated reorientations in NH4Al(SO4) · 12 H2O single crystals

No Thumbnail Available

Date

1990-06-18

Journal Title

Journal ISSN

Volume Title

Publisher

IOP Publishing

Abstract

Single crystals of aluminium ammonium alum NH4Al(SO4)2.12H2O were investigated using dielectric spectroscopy in the frequency range 1 kHz to 1 GHz. On approaching the ferroelectric transition at 58 K from above, a monodispersive polar mode is observed to slow down. The relaxation data can be described in terms of a pure Arrhenius law. The analysis of the dielectric loss reveals that in the paraelectric phase the static susceptibility cannot be described by a single Curie-Weiss law. The thermal variations of the Curie constant indicate that the dipolar correlations of the ammonium ions increase as the temperature is lowered.

Description

Table of contents

Keywords

Citation

Böhmer, R.; Lunkenheimer, P.; Vij, J. K.; Svare, I.: Correlated reorientations in NH4Al(SO4) · 12 H2O single crystals. In: Journal of Physics: Condensed Matter Nr. 24, Jg. 2(1990), S. 5433-5438, doi: 10.1088/0953-8984/2/24/014.