Virginia Tech
Multiferroic Bismuth Ferrite-Lead Titanate and Iron-Gallium Crystalline Solutions: Structure-Property Investigations
Abstract
dc:description.abstractRecently, multiferroics-defined as materials with coexistence of at least two of the ferroelectric, ferroelastic and ferromagnetic effects-have attracted enormous research activities. In this thesis, the structure and properties of multiferrioic BiFeO3-x%PbTiO3 and Fe-x%Ga crystalline solutions were investigated. First, the results show that modified BiFeO3-PbTiO3 based ceramics have significantly enhanced multiferroic properties, relative to BiFeO3 single crystals. The data reveal: (i) a dramatic increase in the induced polarization; and (ii) the establishment of a remnant magnetization by a breaking of the translational invariance of a long-period cycloidal spin structure, via substituent effects. In addition, temperature dependent magnetic permeability investigations of BiFeO3-xPbTiO3 crystalline solutions have shown that aliovalent La substitution results in a significant increase in the permeability. Second, room temperature high-resolution neutron and x-ray diffraction studies have been performed on Fe-x%Ga crystals for 12<x<25at%. It has been observed that the structures of both Fe-12%Ga and Fe-25%Ga are tetragonal; however, near the phase boundary between them, an averaged-cubic structure was identified. In addition, an unusual splitting along the transverse direction indicates that the crystals are structurally inhomogeneous.
Degree
thesis:*- Name thesis:degree_name
- Master of Science
- Level thesis:degree_level
- masters
- Discipline thesis:degree_discipline
- Materials Science and Engineering
- Department dc:contributor.department
- Materials Science and Engineering
- Grantor dc:publisher
- Virginia Tech
- Year dc:date.issued
- 2005
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Wang, Naigang
- Chair dc:contributor.committeechair
-
- Viehland, Dwight D.
- Committee members dc:contributor.committeemember
-
- Reynolds, William T. Jr.
- Li, Jie-Fang
Subjects
dc:subject × 4Rights
dc:rights- Statement dc:rights
-
- In Copyright
- Licence dc:rights.uri
Identifiers
dc:identifier.*- Dc Identifier Other
- etd-07012005-173326
- OAI identifier oai:identifier
- oai:vtechworks.lib.vt.edu:10919/33854