|About this Abstract
||Materials Science & Technology 2012
||International Symposium on Defects, Transport and Related Phenomena
||SrTiO3 as Master Example of Nanosize Effects in Mixed Conducting Oxides
||Giuliano Gregori, Piero Lupetin, Joachim Maier
|On-Site Speaker (Planned)
Grain boundaries (GBs) can have a profound impact on the electrical conductivity of many oxides, as near the charged boundaries (space charge layer – SCL), the mobile charge carriers concentrations deviate from the values determined by the bulk defect chemistry. Such an effect is crucial in nanocrystalline materials because the GBs density is large and because the SCL extension can be comparable with the average grain size. In this contribution, we illustrate which drastic consequences for electronic and ionic conductivities the SCL effects can induce in nanocrystalline SrTiO<SUB>3</SUB>. For this purpose, the conduction properties of undoped, acceptor-doped (iron) as well as donor-doped (niobium) nanocrystalline SrTiO<SUB>3</SUB> are discussed within the framework of the space charge theory. Remarkably, while the experimental data of the undoped and the acceptor-doped SrTiO<SUB>3</SUB> are explained by a positive SCL potential, the donor-doped SrTiO<SUB>3</SUB> indicate the presence of a net negative charge in the GBs core.