Boson Physics and Vortex Pinning Via Splayed Columnar Defects in Superconductors
Concepts from many particle nonrelativistic quantum mechanics can be used to understand vortex line fluctuations in high-temperature superconductors. Flux lines are essentially classical objects, described by a string tension, their mutual repulsion, and interactions with pinning centers. The classical partition function, however, is isomorphic to the imaginary time path integral description of boson quantum mechanics. Recent double-sided decoration experiments in BSCCO compounds in a frozen flux liquid state have now revealed the “phonon-roton” spectrum which describes the decay of density fluctuations along the field direction. Parallel columnar pins lead to a low temperature “Bose glass” phase. Controlled splay of artificial columnar defects in cuprate superconductors can enhance transport properties in a field compared to parallel columns. The theory predicts a new “splayed glass” characterized by a greatly reduced flux creep and an entangled ground state similar to dislocation tangles in a work hardened metal. Recent experiments suggest that controlled splay leads to significant improvements in critical currents.
KeywordsVortex Line Flux Line Cuprate Superconductor Barium Copper Columnar Defect
Unable to display preview. Download preview PDF.
- 2.A.A. Abrikosov, Zh. Eksperim. i. Theor. Fix. 32, 1442 (1957)Google Scholar
- 2a.A.A. Abrikosov, [Sov. Phys. JETP 5, 1174 (1957)].Google Scholar
- 3.M. Charalambous, J. Chaussy and P. Lejay, Phys. Rev. B45, 45 (1992).Google Scholar
- 9.D.R. Nelson and P. Le Doussal, Phys. Rev. B42, 10112 (1991).Google Scholar
- 17a.R.P. Feynman, Statistical Mechanics (Benjamin, Reading, MA, 1972).Google Scholar
- 19.D.R. Nelson, in Phenomenology and Applications of High-Temperature Superconductors, edited by K. Bedell et al. (Addison-Wesley, New York, 1991); andGoogle Scholar
- 19a.D.R. Nelson, in The Vortex State, edited by N. Bontemps et al. (Kluwer, Boston, 1994).Google Scholar
- 21.M.C. Marchetti and D.R. Nelson, Phys. Rev. B47, 214 (1993);Google Scholar
- 23.L. Krusin-Elbaum, A.D. Marwick, R. Wheeler, C. Feild, V.M. Vinokur, G.K. Leaf and M. Palumbo, IBM. T.J. Watson Laboratory preprint. Interestingly, Gaussian splay was found to be less effective than a simple bimodal splay at ±5° in this experiment.Google Scholar