  We have made magnetization and x-ray diffraction measurements on an epitaxial
Pb(Fe1/2Nb1/2)O3 200 nm film. From the temperature dependence of the
out-of-plane lattice parameter we can assign a Burns' temperature at Td ~ 640
K, a temperature at T* ~ 510 K, related to the appearance of static polar
nanoregions, and an anomaly occurring at 200 K. The latter is precisely the
N\'eel temperature TN determined from magnetization and points to spin-lattice
coupling at TN ~ 200 K. We also observe "weak ferromagnetism" up to 300K and
propose superantiferromagnetic clusters as a plausible scenario to explain this
hysteresis above TN.
