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

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, 0 less than or equal to 7 degrees, where 0 is an angle betwee n magnetic field and the film surface. It is expected from the film geometr y with a large aspect ratio (width/thickness) that M is dominated by the pe rpendicular magnetization (M-c) due to the shielding current flowing in the ab plane. However, pie have first demonstrated that there is considerable contribution from the magnetization along the ab plane (M-ab) when a medium field (approximate to0.1 T) is applied very close to the film surface (0 l ess than or equal to 0.4-2.0 degrees, depending on temperature). We investi gated the temperature and field dependence of hysteretic magnetization to o utline the behavior of the hysteresis loss in an inclined field in practica lly interesting conditions. (C) 2001 Published by Elsevier Science Ltd.