Angular dependence of the disorder crossover in the vortex lattice of Bi2.15Sr1.85CaCu2O8+δ by muon spin rotation and torque magnetometry

Using the techniques of muon spin rotation and torque magnetometry, we investigate the crossover field B-cr in Bi2.15Sr1.85Ca1Cu2O8+delta at which the vortex lattice becomes disordered along the field direction. It is found that B-cr scales as the projection of the applied field along the perpendicular to the superconducting planes. This has the implication that a field large enough to give a disordered lattice when applied perpendicular to the planes, can give a well-ordered vortex-line lattice for angles of the field to the c axis greater than a critical value.