Transport measurements in the flux transformer and c-axis geometries are used to investigate vortex dynamics in heavy ion irradiated BSCCO crystals. In the flux transformer geometry there is a range of fields, temperatures, and angles where the primary and secondary voltages show close correspondence, as observed in YBCO. This occurs because the columnar defects suppress thermal fluctuations and decrease r c. Values for r ab and r c are extracted from the flux transformer data assuming local anisotropic electrodynamics and compared with directly measured c-axis data. Good agreement confirms the validity of local resistivity. This is supported by both measurement configurations indicating that r c vanishes faster than r ab. [S0031-9007(96)00874-5]

Multiterminal measurements have been made on Bi 2 Sr 2 CaCu 2 O 8 crystals to investigate the vortex dimensionality at the fields and temperatures where the first-order transition takes place in the vortex lattice. A sharp hysteretic transition is seen in transport properties with current injected either parallel or perpendicular to the ab planes. The data indicate that both resistivity components disappear concurrently, and the melting and c-axis decoupling transitions occur simultaneously at a sublimation transition of the vortex lattice. ͓S0163-1829͑97͒05110-2͔

The c-axis resistivity, c (B,T,), where is the angle between the c axis and the dc field, has been measured for Bi 2 Sr 2 CaCu 2 O 8 single crystals before and after the introduction of columnar defects by heavy ion irradiation. The effects of different columnar track density and angle with respect to the basal plane are also investigated. Uniaxial enhancement of the irreversibility line for fields below the matching field and parallel to the columnar defects is observed in out-of-plane transport measurements. Measurements in the flux transformer geometry confirm that the vortices are connected lines in the irradiated crystal. We have also attempted to reconcile c-axis data with the predictions of the Bose-glass theory for correlated disorder. ͓S0163-1829͑96͒01621-9͔

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