Abstract
Resistive transition curves of a La1.85Sr0.15CuO4 single-crystal thin film have been measured for various magnetic fields and angles between the CuO plane and the field. Using the mean-field approach to determine T c(H), the upper critical field H c2 and its angular dependence are estimated. For the magnetic fields parallel and perpendicular to the CuO plane, values for dH c2 ///dT=-11.8T/K and dH c2 /dT=-1.0T/K are obtained, resulting in an anisotropy factor of 12. The angular dependence of dH c2/dT is explained well by the effective mass model. The Ginzburg-Landau coherence lengths are 32 Å in the CuO plane and 2.7 Å in the c-axis direction.