  We report the study of magnetic and orbital order in
Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ epitaxial thin films grown on
(LaAlO$_3$)$_{0.3}$-(SrAl$_{0.5}$Ta$_{0.5}$O$_3$)$_{0.7}$ (LSAT) (011)$_c$. In
a new experimental approach, the polarization and energy dependence of resonant
soft x-ray scattering are used to reveal significant modifications of the
magnetic order in the film as compared to the bulk, namely (i) a different
magnetic ordering wave vector, (ii) a different magnetic easy axis and (iii) an
additional magnetic reordering transition at low temperatures. These
observations indicate a strong impact of the epitaxial strain on the spin
order, which is mediated by the orbital degrees of freedom and which provides a
promising route to tune the magnetic properties of manganite films. Our results
further demonstrate that resonant soft x-ray scattering is a very suitable
technique to study the magnetism in thin films, to which neutron scattering
cannot easily be applied due to the small sample volume.
