BEGIN:VCALENDAR
VERSION:2.0
PRODID:icalendar-ruby
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VEVENT
DTSTAMP:20240329T082724Z
UID:https://www.mpie.de/events/17209/2656480
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 SrTiO3 and our first attempts on dislocation creep in BaTiO3. 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).\nVortragende(r): Prof. Jürgen Rödel
LAST-MODIFIED:20190110T102717Z
LOCATION:Max-Planck-Institut für Eisenforschung GmbH\, Raum: Large Confere
nce Room No. 203
ORGANIZER:on invitation of Dr. Christian Liebscher and Prof. Gerhard Dehm
SUMMARY:MPIE Colloquium: Dislocation-based Functionality in Oxides
URL:https://www.mpie.de/events/17209/2656480
END:VEVENT
END:VCALENDAR