SrxBa1−xNb2O6−δ Ferroelectric-Thermoelectrics: Crystal Anisotropy, Conduction Mechanism, and Power Factor

Applied Physics Letters (Impact Factor: 3.3). 01/2010; 96(3):031910. DOI: 10.1063/1.3291563


Nonstoichiometric tungsten bronze-structured ferroelectric SrxBa1-xNb2O6-d (SBN) single crystals were found to be a promising n-type thermoelectric oxide. Thermopower anomalies were observed at the phase transition temperatures, depending on the degree of reduction as well as crystal anisotropy. Above 500 K, heavily reduced SBN crystals show high thermoelectric power factors (~20 W/cm K2 at 516 K) with both thermopower and electrical conductivity higher parallel to the c-axis. It is noted that the power factor increases with temperature due to the semiconducting behavior with high carrier concentration. The carrier transport mechanism also varies with the degree of reduction and temperature.

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Available from: Soonil Lee
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    • "Tungsten bronze (TTB) oxides are the largest dielectric family just after perovskites, and their interesting dielectric and ferroelectric properties have attracted systematic research activities towards gathering understanding on their structural and physical properties. The main promising applications for TTBs include nonlinear optics [1], thermoelectrics [2], electrocalorics for refrigeration applications [3], temperature stable multilayer capacitors (MLCC) [4], among others. The tetragonal tungsten bronze structure consists of layers of distorted BO 6 octahedra sharing corners in such a way that three different types of interstices (pentagonal A1, square A2 and trigonal C) are available for cation occupancy ( "
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