Anisotropic superconducting strip in an oblique magnetic field

The critical state of a thin superconducting strip in an oblique applied magnetic field Hₐ is analyzed without any restrictions on the dependence of the critical current density jc on the local magnetic induction B. In such a strip, jc is not constant across the thickness of the sample and differs from Jc∕d, where Jc is the critical sheet current. It is shown that in contrast to the case of B-independent jc, the profiles Hz(x) of the magnetic-field component perpendicular to the strip plane generally depend on the in-plane component Hₐₓ of the applied magnetic field Hₐ and on how Hₐ is switched on. On the basis of this analysis, we explain how and under what conditions one can extract jc(B) from the magnetic-field profiles Hz(x) measured by magneto-optical imaging or by Hall-sensor arrays at the upper surface of the strip.