Vortex dynamics in Bi2Sr2CaCu2O8+δ single crystals with planar defects

We have studied the effects of c-axis correlated planar defects on the vortex lattice of Bi2Sr2CaCu2O8 single crystals using Bitter decoration, transverse ac permeability and X-ray measurements. Our results show that the low field low temperature phase coherent vortex lattice exhibits anisotropic pinning in the presence of these planar defects. Frequency dependent ac permeability measurements show that the ordered solid–liquid transition is first order as in samples free of correlated defects. However, the melting point is detected only when the excitation field is along the defects.