  The ground state and the finite temperature phase diagrams with respect to
magnetic configurations are studied systematically for thin magnetic films in
terms of a classical Heisenberg model including magnetic dipole-dipole
interaction and uniaxial anisotropy. Simple relations are derived for the
occurrence of the various phase boundaries between the different regions of the
magnetic orientations. In particular, the range of the first and second order
reorientation phase transitions are determined for bi- and trilayers.
