Effect of grain boundaries on magnetic field penetration in polycrystalline superconductors

T. L. Hylton; M. R. Beasley

doi:10.1103/PhysRevB.39.9042

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Effect of grain boundaries on magnetic field penetration in polycrystalline superconductors

T. L. Hylton, M. R. Beasley

DOI 10.1103/PhysRevB.39.9042 · Physical Review B

T1

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Abstract

The magnetic-field penetration at grain boundaries in superconductors is calculated using a model in which the grains and the grain boundaries are treated on an equal basis. The grains are modeled using the London theory, and the grain boundaries as weak-link Josephson junctions in the linear regime. An exact solution is found. Calculations of the overall effective penetration depth are presented for regular laminar arrays of grain boundaries for arbitrary grain size, diagonal grain anisotropy, and grain boundary coupling. Analytical formulas are obtained in several limiting cases, and simple empirically fit formulas are presented that are applicable in most intermediate regimes of grain size and grain coupling. The relevance of the results to the high-temperature oxide superconductors is discussed.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
La3Ni2O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown