Muon-spin rotation spectra in the mixed phase of high-T-c superconductors: Thermal fluctuations and disorder effects


Autoria(s): Menon, Gautam I; Dasgupta, Chandan; Ramakrishnan, TV
Data(s)

01/09/1999

Resumo

We study muon-spin rotation (mu SR) spectra in the mixed phase of highly anisotropic layered superconductors, specifically Bi2+xSr2-xCaCu2O8+delta (BSCCO), by modeling the fluid and solid phases of pancake Vortices using liquid-state and density functional methods. The role of thermal fluctuations in causing motional narrowing of mu SR line shapes is quantified in terms of a first-principles theory of the flux-lattice melting transition. The effects of random point pinning are investigated using a replica treatment of liquid-state correlations and a replicated density functional theory. Our results indicate that motional narrowing in the pure system, although substantial, cannot account for the remarkably small linewidths obtained experimentally at relatively high fields and low temperatures. We find that satisfactory agreement with the mu SR data for BSCCO in this regime can be obtained through the ansatz that this ''phase'' is characterized by frozen short-range positional correlations reflecting the structure of the liquid just above the melting transition. This proposal is consistent with recent suggestions of a ''pinned liquid'' or ''glassy'' state of pancake Vortices in the presence of pinning disorder. Our results for the high-temperature liquid phase indicate that measurable linewidths may be obtained in this phase as a consequence of density inhomogeneities induced by the pinning disorder. The results presented here comprise a unified, first-principles theoretical treatment of mu SR spectra in highly anisotropic layered superconductors in terms of a controlled set of approximations. [S0163-1829(99)08033-9].

Formato

application/pdf

Identificador

http://eprints.iisc.ernet.in/38681/1/Muon-spin_rotation_spectra.pdf

Menon, Gautam I and Dasgupta, Chandan and Ramakrishnan, TV (1999) Muon-spin rotation spectra in the mixed phase of high-T-c superconductors: Thermal fluctuations and disorder effects. In: Physical Review B: Condensed Matter, 60 (10). pp. 7607-7622.

Publicador

The American Physical Society

Relação

http://prb.aps.org/abstract/PRB/v60/i10/p7607_1

http://eprints.iisc.ernet.in/38681/

Palavras-Chave #Physics
Tipo

Journal Article

PeerReviewed