Der Einfluss von Defekten auf das Schaltverhalten ferroelektrisch modulierter Substanzen

Behrendt, Karsten

dc.contributor.advisor	Eckold, Götz Prof. Dr.
dc.contributor.author	Behrendt, Karsten
dc.date.accessioned	2016-04-26T09:56:49Z
dc.date.available	2016-04-26T09:56:49Z
dc.date.issued	2016-04-26
dc.identifier.uri	http://hdl.handle.net/11858/00-1735-0000-0028-873E-C
dc.identifier.uri	http://dx.doi.org/10.53846/goediss-5628
dc.language.iso	deu	de
dc.publisher	Niedersächsische Staats- und Universitätsbibliothek Göttingen	de
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject.ddc	540	de
dc.title	Der Einfluss von Defekten auf das Schaltverhalten ferroelektrisch modulierter Substanzen	de
dc.type	doctoralThesis	de
dc.title.translated	The influence of defects on the switching behaviour of ferroelectric modulated substances	de
dc.contributor.referee	Eckold, Götz Prof. Dr.
dc.date.examination	2015-07-21
dc.description.abstracteng	The influence of defects on the phase transition behavior of A2BX4-compounds was studied by diffraction methods, impedance spectroscopy and atomic force microscopy. It was found that chemical point defects have a strong effect on the transition kinetics, whereas the thermodynamic stability of different modulated phases is only slightly affected by such doping with alkali ions. The lock-in-transition from incommensurate to commensurate modulated is slowed down by several orders of magnitude. The transition time hereby ranges from minutes to months, depending on impurity concentration. Due to this, metastable incommensurate phases can be obtained at room temperature. These undercooled phases exhibit remarkable structural and dielectric properties, such as polar nanodomains. The metastable phases undergo additional phase transitions into newly discovered commensurate phases. A unique property of those phases is a memory effect, which allows the incommensurate phase to be re-formed upon subsequent heating. A detailed microscopic model is discussed, which describes all aspects of the observed behavior. This model is based on the formation of a defect density wave and considers its interaction with discommensurations in the incommensurate phase. The thermodynamic properties of all observed phases can be deduced from this model.	de
dc.contributor.coReferee	Stalke, Dietmar Prof. Dr.
dc.contributor.thirdReferee	Mata, Ricardo Prof. Dr.
dc.contributor.thirdReferee	Vana, Philipp Prof. Dr.
dc.contributor.thirdReferee	Zeuch, Thomas Dr.
dc.contributor.thirdReferee	Meyer, Franc Prof. Dr.
dc.subject.eng	ferroelectric	de
dc.subject.eng	incommensurate	de
dc.subject.eng	defects	de
dc.subject.eng	phase transition	de
dc.subject.eng	permittivity	de
dc.subject.eng	kinetics	de
dc.subject.eng	atomic force microscopy	de
dc.subject.eng	impedance spectroscopy	de
dc.subject.eng	diffraction	de
dc.subject.eng	metastable phases	de
dc.identifier.urn	urn:nbn:de:gbv:7-11858/00-1735-0000-0028-873E-C-4
dc.affiliation.institute	Fakultät für Chemie	de
dc.subject.gokfull	Chemie (PPN62138352X)	de
dc.identifier.ppn	857532235

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Fakultät für Chemie (inkl. GAUSS) [701]

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