Abstract
The A-B interface of superfluid He3 was studied with use of Ginzburg-Landau theory. The effect of a magnetic field on the interface structure was calculated. The surface tension of the interface was found to vanish rapidly when approaching the weak-coupling limit. By doing perturbation theory around this limit, an analytic expression for the interface tension was found that presumably is accurate for arbitrary physical values of the strong-coupling parameters. The effect of the dipole interaction was studied in both low and high magnetic fields. The rotation axis of the B phase was found to deviate substantially from the direction of the magnetic field near the interface.