Magnetic flux rotation and associated magnetization peak in La1.85 Sr0.15 CuO4 crystals under tilted fields

The magnetization vector in La1.85 Sr0.15 CuO4 was measured as a function of magnetic field, temperature and time for fields tilted from the ab plane. For small tilting angles, the magnetization amplitude curves exhibit an additional peak in between the well-known first and second magnetization peaks. Assessment of the induction vector as a function of field reveals flux rotation from the ab plane towards the direction of the external field, beginning at the onset of the additional magnetization peak. This flux rotation causes a tilt of the current flow plane towards an "easy" direction, namely, the ab plane. The additional peak results from a competition between the current increase associated with this tilt and the intrinsic current decrease associated with the field increase.