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VERSION:2.0
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METHOD:PUBLISH
BEGIN:VEVENT
DTSTAMP:20261002T134233Z
UID:https://www.mpie.de/events/17209/3755656
DTSTART:20190117T100000Z
DTEND:20190117T110000Z
CLASS:PUBLIC
CREATED:20181220T094349Z
DESCRIPTION:Dislocations in oxides are typically heavily charged and are su
 rrounded by compensating electric charges. As such they are kinetically mo
 re stable than chemical dopants. Adepalli et al. termed dislocations a mea
 ns for “one-dimensional doping” [1]. As they are often introduced by m
 echanical methods\, they may also be termed “mechanical doping” or “
 self-doping”\, as the charges derive from local concentration of the mat
 rix elements. In the literature dislocations have been demonstrated to enh
 ance oxygen conductivity [1] and improve the figure of merit of thermoelec
 trics by reducing thermal conductivity through phonon scattering by disloc
 ations [2]. Dislocations have been suggested to improve interfacial reacti
 on kinetics and have been theoretically predicted to pin domain walls in f
 erroelectrics. In Darmstadt we have so far focused on establishing a set o
 f techniques to introduce dislocations into single crystals at room temper
 ature or enhanced temperature and to study (dislocation) creep. Structural
  investigations have been performed by dark-field X-ray diffraction\, rock
 ing curve analysis [3]\, TEM\, NMR and EPR techniques. The first property 
 evaluations have been done with respect to electrical and thermal conducti
 vity and domain wall pinning. All this has to be seen with the perspective
  of a just developing field\, with many opportunities\, many obstacles and
  a lot of exciting uncertainty. Select examples will be provided on disloc
 ation structures\, electrical and thermal conductivity in SrTiO<sub>3</sub
 > and our first attempts on dislocation creep in BaTiO<sub>3</sub>. Time p
 rovided\, I will show 4 slides on the small brother field: “Elastic-defo
 rmation tuned conductivity in piezoelectric ZnO." [1] Adepalli\, K. K.\, K
 elsch\, M.\, Merkle\, R.\, and Maier\, J.\, "Enhanced ionic conductivity i
 n polycrystalline TiO2 by "one-dimensional doping''\," Phys. Chem.Chem. Ph
 ys.\, 16[10] 4942-51 (2014). [2] S. Il Kim\, K. H. Lee\, H. A. Mun\, S. H.
  Kim\, S. W. Hwang\, J. W. Roh\, D. J. Yang\, W. H. Shin\, X. S. Li\, Y. H
 . Lee\, G. J. Snyder\, S. W. Kim\, “Dense dislocation arrays embedded in
  grain boundaries for high-performance bulk thermoelectrics“\, Science\,
  348\, 109-114 (2015). [3] E.A. Patterson\, M. Major\, W. Donner\, K. Durs
 t\, K.G. Webber and J. Rödel\, „Temperature dependent deformation and d
 islocation density in SrTiO3 single crystals”\, J. Amer. Ceram. Soc.\, 9
 9\, 3411-120 (2016).\nSpeaker: Prof. Jürgen Rödel
LAST-MODIFIED:20190110T102717Z
LOCATION:Max-Planck-Institut für Eisenforschung GmbH\, Room: Large Confere
 nce Room No. 203
ORGANIZER;CN=on invitation of Dr. Christian Liebscher and Prof. Gerhard Deh
 m:mailto:stein@mpie.de
SUMMARY:MPIE Colloquium: Dislocation-based Functionality in Oxides
URL;VALUE=URI:https://www.mpie.de/events/17209/3755656
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