Publication Date

2019

Document Type

Dissertation/Thesis

First Advisor

Dąbrowski, Bogdan

Degree Name

Ph.D. (Doctor of Philosophy)

Department

Department of Physics

LCSH

Condensed matter||Physics

Abstract

Multiferroic materials having unusual properties of simultaneous presence of ferroelectricity (FE) and magnetism, such that FE can be controlled by magnetic field and magnetization by electric field have attracted interest due to their promising applications in electrically controllable microwave elements, magnetic field sensors, and possibly in spintronics. In this dissertation, the single phase and single ion multiferroic properties of the ceramic oxide antiferromagnets (AFM) Sr[sub 1-x]Ba[sub x]Mn[sub 1-y]TiyO[sub 3] with perovskite structure are discussed. These compounds were designed and developed in our laboratory by understanding critical parameters controlling FE and magnetic properties, advancing the synthesis processes, studying the structural behavior and intricate transitions, and characterizing dielectric and magnetic properties over the complex phase diagram of the manganites system. Multiferroelectricity was achieved by forcing bonds between magnetic transition metals and oxygen under internal tension through the proper selection of the sizes and charges of the A-site and B-site cations as predicted based on the Goldschmidt tolerance factor. Synchrotron X-ray diffraction (XRD) and Neutron powder diffraction (NPD) experiments were used to study the structural, FE and magnetic properties. In the conventional FE titanates BaMn[sub 1-y]TiyO[sub 3], the solubility limit of manganese was extended to 1-y ~ 0.16, and the XRD data taken at Argonne's National Laboratory Advanced Photon Source showed increased temperatures of the coupled structural-ferroelectric transitions above 400 K. A complete solid solution range of manganese ion on the Ti-site was obtained in SrMn[sub 1-y]TiyO[sub 3] (0

Comments

Committee members: Brown, Dennis; Chmaissem, Omar; Ito, Yasuo; Sunderlin, Lee.||Advisor: Dabrowski, Bogdan.||Includes bibliographical references.

Extent

158 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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