Characterization of manganese-oxide perovskites, exhibiting a colossal magnetoresistance
| dc.contributor.advisor | Goodenough, John B. | en |
| dc.creator | Liu, Guoliang | en |
| dc.date.accessioned | 2008-08-28T21:33:25Z | en |
| dc.date.available | 2008-08-28T21:33:25Z | en |
| dc.date.issued | 2003 | en |
| dc.description.abstract | The complex phase diagrams of the La1-xSrxMnO3 ( 0 ≤ x ≤ 0.35), La 1- xCaxMnO3 ( 0 ≤ x ≤ 0.40 ), and R0.7A0.3MnO3 ( 0.949 ≤ t ≤ 0.997 ) systems, in which R is one or more the trivalent rare earth ions, A is one or two divalent alkaline earth, and t is tolerance factor, are presented; they were mapped out with measurements of resistivity ρ(T), thermoelectric power α(T), specific-heat Cp(T), and magnetization M(T) on a series of melt-grown single-crystal samples. A transition from localized to itinerant behavior of electrons of e-orbital parentage in the presence of a localized t3 configuration with spin S = 3/2 was shown to be characterized by an electronic phase segregation into orbitally ordered, electron-rich antiferromagnetic regions and orbitally disordered, conductive ferromagnetic regions that grow in an applied magnetic field. This two-phase electronic character in the crossover compositions gives rise to spin-glass behavior and a colossal magnetoresistance. Particular emphasis was placed on the evolution of the specific-heat data Cp(T) on crossing the transition from localized to itinerant electrons and the fact that Cp(T) is suppressed at a spin-glass freezing temperature. | |
| dc.description.department | Electrical and Computer Engineering | en |
| dc.format.medium | electronic | en |
| dc.identifier | b57157042 | en |
| dc.identifier.oclc | 56799194 | en |
| dc.identifier.proqst | 3118046 | en |
| dc.identifier.uri | http://hdl.handle.net/2152/743 | en |
| dc.language.iso | eng | en |
| dc.rights | Copyright is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works. | en |
| dc.subject.lcsh | Perovskite | en |
| dc.subject.lcsh | Manganese oxides | en |
| dc.subject.lcsh | Magnetoresistance | en |
| dc.title | Characterization of manganese-oxide perovskites, exhibiting a colossal magnetoresistance | en |
| dc.type.genre | Thesis | en |
| thesis.degree.department | Electrical and Computer Engineering | en |
| thesis.degree.discipline | Electrical and Computer Engineering | en |
| thesis.degree.grantor | The University of Texas at Austin | en |
| thesis.degree.level | Doctoral | en |
| thesis.degree.name | Doctor of Philosophy | en |