  We have studied the influence of the magnetization on the superconducting
transition temperature ($T_c$) in bi- and trilayers consisting of the
half-metallic ferromagnet La$_{0.67}$Sr$_{0.33}$MnO$_3$ (LSMO) and the
high-temperature superconductor YBa$_2$Cu$_3$O$_{7-\delta}$ (YBCO). We have
made use of tilted epitaxial growth in order to achieve contacts between the
two materials that are partly in the crystallographic $ab$-plane of the YBCO.
As a result of uniaxial magnetic anisotropy in the tilted structures, we
observe sharp magnetization switching behavior. At temperatures close to $T_c$,
the magnetization switching induces resistance jumps in trilayers, resulting in
a magnetization dependence of $T_c$. In bilayers, this switching effect can be
observed as well, provided that the interface to the ferromagnetic layer is
considerably rough. Our results indicate that the switching behavior arises
from magnetic stray fields from the ferromagnetic layers that penetrate into
the superconductor. A simple model describes the observed behavior well. We
find no evidence that the switching behavior is caused by a so-called
superconducting spin-switch, nor by accumulation of spin-polarized electrons.
Observation of magnetic coupling of the ferromagnetic layers, through the
superconductor, supports the idea of field induced resistance switching.
