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Diffuse ferroelectric phase transitions in Pb-substituted $PbFe_{1/2}Nb_{1/2}O_{3}$

Bhat, VV and Umarji, AM and Shenoy, VB and Waghmare, UV (2005) Diffuse ferroelectric phase transitions in Pb-substituted $PbFe_{1/2}Nb_{1/2}O_{3}$. In: Physical Review B, 72 (1).


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We investigate effects of cation (K, Ca, Sr, Ba, La, Bi, Tl, Ag)substitution at Pb-site in PbFe1/2Nb1/2O3 (PFN) on its diffuseferroelectric phase transition (DPT) through measurements and modelingof the temperature dependence of its dielectric constant. We find thatthe chemical trends in experimentally determined rates of change oftransition temperature and diffuseness with substituent concentrationare governed by two parameters, nominal and Born effective chargescalculated within first-principles density functional theory. Weintroduce "ferroactivity" of an atom using these charges and use it ina generalized Weiss molecular field theory that accounts for thedisorder to explain chemical trends in the DPT found experimentally,suggesting guidelines to tune properties of ferroelectrics.

Item Type: Journal Article
Publication: Physical Review B
Publisher: American Physical Society
Additional Information: Copyright for this article belongs to American Physical Society.
Department/Centre: Division of Chemical Sciences > Materials Research Centre
Division of Physical & Mathematical Sciences > Physics
Date Deposited: 08 Sep 2005
Last Modified: 19 Sep 2010 04:20
URI: http://eprints.iisc.ac.in/id/eprint/3616

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