Electrical and optical investigations of Rb2ZnCl4 crystals in the vicinity of the incommensurate phase

Issue		Eur. Phys. J. Appl. Phys. Volume 4, Number 1, October 1998


Page(s)		5 - 9
DOI		10.1051/epjap:1998239

DOI: 10.1051/epjap:1998239

Eur. Phys. J. AP 4, 5-9

Electrical and optical investigations of Rb $\mathsf{_{2}}$ ZnCl $\mathsf{_{4}}$ crystals
in the vicinity of the incommensurate phase

A. Abu El-Fadl

Physics Department, Faculty of Science, Assiut University, Assiut, Egypt

Received: 27 February 1998 / Revised and Accepted: 28 May 1998

Abstract
Temperature dependence of the dielectric constant $\epsilon$ and the electrical resistivity $\rho$ of Rb₂ZnCl₄ (RZC) along the three crystallographic axes were measured between 260 and 360 K. The electrical measurements clearly reveal the paraelectric incommensurate phase around 303 K. Peaks in the dielectric constants $\epsilon_{a}$ and $\epsilon_{b}$ were observed at this transition temperature. The results of the electrical resistivity were analyzed and the activation energies of conduction at different temperature regions were evaluated. The dependence of the absorption coefficient $\alpha$ on the photon energy and on temperature near the fundamental absorption edge was measured. Exponential dependence of that coefficient according to the Urbach's rule was observed and the Urbach parameters were determined and their temperature dependence was investigated. The temperature gradient of the band gap $(\partial E_{g}/\partial T)$ reveals an anomaly at the incommensurate paraelectric phase. The indirect band gap was shifted towards the longer wavelength (red shift) with increasing temperature. This behaviour could be interpreted in terms of electron lattice interaction and crystal field splitting.

PACS
64.70.Rh Commensurate incommensurate transitions - 78.20.-e Optical properties of bulk
materials and thin films

Author for correspondance: assiut@frcu.eun.eg

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.

Electrical and optical investigations of RbZnCl crystals in the vicinity of the incommensurate phase

Electrical and optical investigations of Rb $\mathsf{_{2}}$ ZnCl $\mathsf{_{4}}$ crystals
in the vicinity of the incommensurate phase