Penetration of Josephson vortices and measurement of the c-axis penetration depth in Bi2Sr2CaCu2O8+delta: Interplay of Josephson coupling, surface barrier, and defects - art. no. 144525

The first penetration field H-e(T) of Josephson vortices is measured throug h the onset of microwave absorption in the locked state in slightly overdop ed Bi2Sr2CaCu2O8+delta single crystals (T(c)approximate to 84 K). The magni tude of H-e(T) is too large to be accounted for by the first thermodynamic critical field H-cl(T). We discuss the possibility of a Bean-Livingston bar rier, also supported by irreversible behavior upon flux exit, and the role of defects, which relates H-e(T) to the c-axis penetration depth lambda (c) (T). The temperature dependence of the latter, determined by a cavity pertu rbation technique, and a theoretical estimate of the defect-limited penetra tion held are used to deduce from H-e(T) the absolute value of lambda (c)(0 )approximate to 35 mum.