ANOMALOUS BEHAVIOR OF THE INTERLAYER RESISTANCE OF A BSCCO-2212 CRYSTAL IN A PARALLEL MAGNETIC-FIELD

The electrical resistance across the Cu-O layers of a BSCCO-2212 singl e crystal is investigated in the range of angles 0 degrees less than o r equal to phi less than or equal to 90 degrees between the magnetic f ield H less than or equal to 15 T and the ab plane, It is found that t he temperature dependence R(T) at the transition into the mixed state is much sharper for phi similar or equal to 0 degrees than for 1 degre es less than or similar to phi less than or similar to 90 degrees, whe re R is determined by the perpendicular component of the magnetic fiel d and is described by the Arrhenius law R similar to exp(-U/T). For H parallel to ab hysteretic jumps in R(T,H), which vanish as the current increases, are observed at fields in the range 5.5 less than or equal to H less than or equal to 11 T. This effect can be attributed to a c ommensurate phase transition in a lattice of Josephson vortices.