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DF: Fachverband Dielektrische Festkörper
DF 4: Multiferroics, Phase Transitions & Relaxors
DF 4.6: Vortrag
Montag, 23. März 2009, 12:00–12:20, WIL B321
Pressure-induced local structural changes in PSN, PSN:Ba and PSN:Bi — •Anna-Maria Welsch1, Boriana Mihailova1, Marin Gospodinov2, Rainer Stosch3, Bernd Guettler3, and Ulrich Bismayer1 — 1Universität Hamburg — 2Bulgarian Academy of Sciences — 3PTB Braunschweig
Relaxors represent a special class of ferroelectrics which are attractive for a number of technological applications due to their unusual dielectric properties, intimatelly related to the presence of polar nano-domains within paraelectric matrix. Majority of relaxors are of Pb-based perovskite-type structure with general formula being ABO3, which enables substitutional disorder in both A- and B-sites. Different types of cations on A- and B- positions and their degree of order have a direct influence on the formation and behaviour of polar nano-domains. In the recent years pressure came forth as a very powerful experimental approach in investigating the origin and true mechanism of relaxor behaviour, both still elusive to this day in spite of years of extensive research. Pressure acts directly on the inter-atomic level and combined with variations in the chemical composition influence the nano-domain structure and desired relaxor properties.
Here we present our results on the structure of pure, Ba- and Bi-containing PbSc0.5Nb0.5O3. The pressure-induced structural changes of differently A-site doped compounds were studied by Raman spectroscopy. Our results indicate that pressure induces structural changes, favouring a certain type of ferroic distortion, with varying degree relative to the type and stereochemical nature of the A-site cations.