Hysteresis losses in thick YBCO films: a linear componential analysis of magnetization in nearly parallel magnetic fields

摘要

We investigated the magnetization (M) hysteresis loops of micron-thick, c-axis-oriented YBCO films in magnetic fields applied nearly parallel to the film surface, #theta# <= 7 deg, where #theta# is an angle between magnetic field and the film surface. It is expected from the film geometry with a large aspect ratio (width/thickness) that M is dominated by the perpendicular magnetization (M_c) due to the shielding current flowing in the ab plane. However, we have first demonstrated that there is considerable contribution from the magnetization along the ab plane (M_(ab)) when a medium field (approx=0.1 T) is applied very close to the film surface (#theta# <=0.4-2.0 deg, depending on temperature). We investigated the temperature and field dependence of hysteretic magnetization to outline the behavior of the hysteresis loss in an inclined field in practically interesting conditions.