Anisotrophy and applied field effects on the spiral magnetic coexistence state of ferromagnetic superconductors /
| Main Author: | |
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1988.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | The effect of three types of "quartic" anisotropy energy on the polarization of the "spiral-magnetic"-state of Blount and Varma is studied near the onset temperature. We study a quartic anisotropy with uniaxial symmetry, a quartic anisotropy with cubic symmetry, and also, we model the anisotropy in primitive tetragonal ErRh4B4 with a quadratic anisotropy giving a hard c-axis, plus a quartic anisotropy in the basal plane with a square symmetry. The details of the magnetizations, wavevectors, and polarizations are presented. Further, using a variational approach, we investigate the effects, in a slab geometry, of an infinitesimal and finite magnetic field applied parallel to the slab on the spiral magnetic state. By additionally calculating the effects on the normal ferro-paramagnetic state and the uniform superconducting state, we can study applied field vs. temperature phase diagrams. Due to the large experimental uncertainty in the material parameters, an extended range of values is studied producing a number of interesting and physically unique phase diagrams. A categorization of the types of phase diagrams over the selected range of the material parameters is presented. Finally, we calculate the effective superconducting penetration depth in the presence of the spiral-magnetic state. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Physics." |
| Physical Description: | x, 165 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references (leaves 160-164). |