UNCONVENTIONAL ANGULAR-DEPENDENCE OF THE MICROSCOPIC MAGNETIC-FIELD DISTRIBUTION IN SINGLE-CRYSTAL BI2SR2CACU2O8 FROM MUON-SPIN ROTATION STUDIES

The angular dependence of the microscopic magnetic field distribution in single-crystal Bi2Sr2CaCu2O8 has been measured for a range of applied fields using the muon-spin rotation technique. The results show significant deviations from the predictions of the anisotropic 3D model, which may reflect the extremely anisotropic, quasi-2D nature of the flux structure. The temperature dependence of the field distribution at 400 mT has also been measured for a range of orientations, showing disagreement with the predictions of a simple two-fluid model.