Magnetic phase diagram of Ca₂₊xY₂₋xCu₅O₁₀₋[delta]: oxygen hole-doping effects


Magnetic phase diagram of Ca₂₊xY₂₋xCu₅O₁₀₋[delta]: oxygen hole-doping effects

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dc.contributor.advisor Markert, John T.
dc.creator Park, Keeseong, 1972- 2008-08-28T23:36:15Z 2008-08-28T23:36:15Z 2007 2008-08-28T23:36:15Z
dc.description.abstract Oxygen hole-doping effects on a spin-chain system, Ca[subscript 2+chi]Y[2-chi]Cu₅O[subscript 10-delta](CaYCuO) are reported. CaYCuO is a good specimen to study the magnetic properties of the CuO₂ chain at the ground state because it has no complex structure other than the chain and it has hole dopability up to the formal copper valence number of +2.4. Specifically, we can dope holes into the CuO₂ chain by substituting Ca²⁺ for Y³⁺ or by utilizing oxygen deficiency. After a systematic study of the two methods to dope holes, we found that oxygen doping makes a more critical change in magnetic ordering in the chain than the replacement of Ca²⁺. Oxygen deficiency effects of the chain on the magnetic properties were explained using a mean field theory. A new relation for the effective hole doping was found as p = x - [alpha delta], where a = 3/2(x - [delta]) - 1/4. We study the anisotropy of magnetic properties of single crystal Li-cathode material (LiFePO₄) for g-factor, Curie-Weiss temperature, and effective moment. Magnetic properties Au/SiO₂ coated [gamma]-Fe₂O₃ are compared with pure [gamma]-Fe₂O₃ finding a decrease in the blocking temperature and the irreversible temperature for the coated nanoparticles.
dc.format.medium electronic
dc.language.iso eng
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.
dc.subject.lcsh Oxygen--Industrial applications
dc.subject.lcsh Copper oxide superconductors
dc.subject.lcsh Minerals--Magnetic properties
dc.title Magnetic phase diagram of Ca₂₊xY₂₋xCu₅O₁₀₋[delta]: oxygen hole-doping effects
dc.description.department Physics
dc.identifier.oclc 174113855
dc.identifier.recnum b68890060
dc.type.genre Thesis
dc.type.material text Physics Physics The University of Texas at Austin Doctoral Doctor of Philosophy

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