Angular dependence of the disorder crossover in the vortex lattice ofBi2.15Sr1.85CaCu2O8+δby muon spin rotation and torque magnetometry

Abstract

Using the techniques of muon spin rotation and torque magnetometry, we investigate the crossover field B{sub cr} in Bi{sub 2.15}Sr{sub 1.85}Ca{sub 1}Cu{sub 2}O{sub 8+{delta}} at which the vortex lattice becomes disordered along the field direction. It is found that B{sub 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. {copyright} {ital 1998} {ital The American Physical Society}