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

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. / text

Identiferoai:union.ndltd.org:UTEXAS/oai:repositories.lib.utexas.edu:2152/3242
Date28 August 2008
CreatorsPark, Keeseong, 1972-
Source SetsUniversity of Texas
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Formatelectronic
RightsCopyright 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.

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