Magnetic penetration depth and reversible magnetization in single crystals of Bi2Sr2CaCu2O8+δ grown by TSFZ method
Review articleOpen access
A.I Rykov - No affiliation found
2001/09/01 Full-length article DOI: 10.1016/S0921-4534(01)00253-2
Journal: Physica C: Superconductivity
AbstractWe analyze the reversible magnetization in Bi2Sr2CaCu2O8+δ using several theoretical concepts, starting from the London model. The field dependence of the empirical “superfluid density” dM/dlnB is fitted with using the theory of circular cell. Additionally, we take into account the pinning mechanism associated with dislocation structures naturally existing in the crystals grown by travelling-solvent-floating-zone (TSFZ) technique. This allows us to explain: (i) the rapid variation of dM/dlnB at small fields; (ii) the reduction of thermal fluctuation term with respect to the theoretical prediction for decoupled pancakes. In the light of this reduction we derive the curves Hc1(T) and λ2(0)/λ2(T) from the reversible magnetization similar to the ones obtained by direct measurements of Hc1 by micro-Hall AC technique, and with microwave surface impedance, respectively.
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