Ferroelectric, conductive, and dielectric properties of KTiOPO4 at low temperature

Jiang, Q., Womersley, M.N., Thomas, P.A., Rourke, J.P. ORCID: https://orcid.org/0000-0002-8961-1021, Hutton, K.B. and Ward, R.C.C. 2002. Ferroelectric, conductive, and dielectric properties of KTiOPO4 at low temperature. Physical Review B 66 (9) , p. 8. 10.1103/PhysRevB.66.094102

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Abstract

This paper reports the low-temperature dielectric, conducting, and ferroelectric properties of potassium titanyl phosphate, KTiOPO4 (KTP). The change of the dielectric relaxation characteristics as well as the dielectric and conducting properties are related to the decrease of ion hopping frequency with temperature. Between room temperature and 100 K, there are four changes in the behavior of KTP: (i) an increase of K+ activation energy from 0.25±0.02eV to 0.40±0.02eV at 295 K; (ii) a superionic phase transition at ∼170 K, accompanied by an increasing thermal absorption and an abnormal change of the thermal expansion; (iii) a phase transition at 140 K associated with the increase of thermal absorption and spontaneous polarization; (iv) a transition from ionic conduction to electronic conduction, which occurs at a frequency-dependent temperature Ttr=−0.3944f2+12.558f+198.59 (f in MHz). The conductivity of KTP shows a strong dependence on the electric field and, as a result of this, ideal ferroelectric hysteresis loops cannot be observed. Despite this, the ionic conductivity decreases with temperature sufficiently to allow KTP to be ferroelectrically switched below 250 K. The coercive field is found to take values from 4.4 to 7.0 kV/mm between 250 K to 180 K, respectively.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry
Publisher:	American Physical Society
ISSN:	2469-9950
Last Modified:	11 Apr 2023 13:15
URI:	https://orca.cardiff.ac.uk/id/eprint/155175

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