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Yet-Ming Chiang. Soukhojak, Andrey N. (Andrey Nestorovich), 1972- Massachusetts Institute of Technology. Dept. of Materials Science and Engineering. Massachusetts Institute of Technology. Department of Materials Science and Engineering 2005-05-19T15:07:48Z 2005-05-19T15:07:48Z 2002 2002 http://hdl.handle.net/1721.1/16877 51722870 Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2002. Includes bibliographical references. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. An experimental study was carried out to map the compositional dependence of electromechanical behavior and ferroelectric phase stability in the barium, zirconium-codoped sodium bismuth titanate (BNBZT) system for barium concentrations up to 18 mol.% and zirconium concentrations up to 4 mol.%. A number of polycrystalline BNBZT samples has been electromechanically tested under applied electric fields of different frequencies (0.2-47 Hz). A novel model of electromechanical response capable of describing both dynamic and static hysteresis for pure and mixed cases of ferroelectric, antiferroelectric, ferroelastic and paraelectric behavior has been developed. Major electromechanical properties of polycrystalline BNBZT have been identified and compositionally mapped. The peak of electromechanical response (d33 = 400 pC/N) has been found at the composition (Bil/2Nal/2)0.93Bao.07Zro.02Tio.9803. The compositional dependence of ferroelectric phase stability has been mapped by means of a Landau type free energy expansion. A nanodomain relaxation mechanism of frequency dependent electromechanical response of BNBZT has been suggested and is supported by optical and transmission electron microscopy. by Andrey N. Soukhojak. Ph.D. 80 p. 30728469 bytes 30728227 bytes application/pdf application/pdf eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Materials Science and Engineering. High-strain actuation of lead-free perovskites : compositional effects, phenomenology and mechanism Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="92723de9-cf67-42fc-9e34-6b034f7761bc"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>High-strain actuation of lead-free perovskites : compositional effects, phenomenology and mechanism</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2002</PublicationDate> <Authors> <Author> <DisplayName>Soukhojak, Andrey N. (Andrey Nestorovich), 1972-</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Materials Science and Engineering.</Keyword> <Abstract>An experimental study was carried out to map the compositional dependence of electromechanical behavior and ferroelectric phase stability in the barium, zirconium-codoped sodium bismuth titanate (BNBZT) system for barium concentrations up to 18 mol.% and zirconium concentrations up to 4 mol.%. A number of polycrystalline BNBZT samples has been electromechanically tested under applied electric fields of different frequencies (0.2-47 Hz). A novel model of electromechanical response capable of describing both dynamic and static hysteresis for pure and mixed cases of ferroelectric, antiferroelectric, ferroelastic and paraelectric behavior has been developed. Major electromechanical properties of polycrystalline BNBZT have been identified and compositionally mapped. The peak of electromechanical response (d33 = 400 pC/N) has been found at the composition (Bil/2Nal/2)0.93Bao.07Zro.02Tio.9803. The compositional dependence of ferroelectric phase stability has been mapped by means of a Landau type free energy expansion. A nanodomain relaxation mechanism of frequency dependent electromechanical response of BNBZT has been suggested and is supported by optical and transmission electron microscopy.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>