Model of the reversible magnetization of high-. kappa. type-II superconductors: Application to high-temperature superconductors
This dissertation is divided into five sections, each dealing with an aspect of the response of type-2 superconductors to applied magnetic fields. In Section 1, a generalized variational model of a singe vortex is presented, valid in the anisotropic case when the applied magnetic field H is along one of the principal axes. The effects of the anisotropy on pinning forces of individual vortices and on the vortex lattice form are discussed. In Section 2, a variational model of the mixed state is proposed, which permits an analytical calculational of the free energy density F in the Ginzburg-Landau regime. A formula for the reversible magnetization is obtained, valid for the entire field region H{sub c1} {le} H {le} H{sub c2}. The model is further extended to include anisotropy by introducing an effective mass tensor for the case when H is parallel to one of the principal axes. The method permits an accurate determination of H{sub c2} versus temperature T from reversible magnetization measurements, and dH{sub c2}/dT = {minus}1.65 {plus minus} 0.23 T/K is found for a YBa{sub 2}Cu{sub 3}O{sub 7} single crystal for H parallel to the c axis near T{sub c}, implying {xi}{sub ab} (0) = 17 {plus minus} 1 {angstrom}. In Section 3, the reversible magnetization of anisotropic superconductors is considered for the case that H is along an arbitrary direction with respect to the principal axes. In Section 4, it is pointed out that the London model for the reversible magnetization M of high-{kappa} type-2 superconductors in the intermediate-field region is quantitatively incorrect.
- Research Organization:
- Iowa State Univ. of Science and Technology, Ames, IA (United States)
- OSTI ID:
- 5526315
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Model for the reversible magnetization of high-. kappa. Type-2 superconductors: Application to high-temperature superconductor
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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BARIUM OXIDES
MAGNETIZATION
SUPERCONDUCTIVITY
BISMUTH OXIDES
CALCIUM OXIDES
COPPER OXIDES
STRONTIUM OXIDES
TYPE-II SUPERCONDUCTORS
MATHEMATICAL MODELS
YTTRIUM OXIDES
ANALYTICAL SOLUTION
ANISOTROPY
FREE ENERGY
GINZBURG-LANDAU THEORY
HIGH-TC SUPERCONDUCTORS
MAGNETIC FIELDS
MONOCRYSTALS
VARIATIONAL METHODS
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BISMUTH COMPOUNDS
CALCIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
CRYSTALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ENERGY
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
STRONTIUM COMPOUNDS
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
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665411 - Basic Superconductivity Studies- (1992-)