Functional ferroelectric and magnetic materials have played an important role of modern technology in the sensor or storage device industries. Ferroelectricity and ferromagnetism emerge from different origins. However, it is discovered that these two seemingly unrelated phenomena can actually coexist in materials called multiferroics. Since current trends toward device miniaturization have increased interests in combining electronic and magnetic properies into multifunctional materials, multiferroics have attracted great attention. Ferromagnetic ferroelectric multiferroics are especially fascinating not only because they have both ferroic properties, but also because of the magnetoelectric coupling which leads the interaction between the magnetic and electric polarization. Recent theoretical breakthroughs in understanding the coexistence of magnetic and electrical ordering have regenerated a great interests in research of such magnetoelectric multiferroics. The long-sought control of electric polarization by magneticfields was recently discovered in `frustrated magnets', for example the perovskites RMnO3, RMn2O5 (R: rare earth elements), Ni3V2O8, delafossite CuFeO2, spinel CoCr2O4, MnWO4, etc. In this dissertation, I have explored several magnetoelectric materials and multiferroics, which show significant magnetoelectric interactions between electric and magnetic orderings. The objects of my projects are focused on understanding the origins of such magnetoelectric couplings and establishing the magnetic/electric phase diagrams and the spin structures. I believe that my works would help to understand the mechanisms of magnetoelectric effects and multiferroics. / A Dissertation submitted to the Department of Physics in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester, 2012. / October 18, 2012. / dielectric, magnetization, magnetoelectric, multiferroic, polarization / Includes bibliographical references. / Eun Sang Choi, Professor Directing Dissertation; Pedro Schlottmann, Professor Co-Directing Dissertation; Naresh S. Dalal, University Representative; James S. Brooks, Committee Member; Volker Credé, Committee Member; Haidong Zhou, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_183257 |
| Contributors | Hwang, Jungmin (authoraut), Choi, Eun Sang (professor directing dissertation), Schlottmann, Pedro (professor co-directing dissertation), Dalal, Naresh S. (university representative), Brooks, James S. (committee member), Credé, Volker (committee member), Zhou, Haidong (committee member), Department of Physics (degree granting department), Florida State University (degree granting institution) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource, computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
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