  The physical properties of manganites depend strongly on sample morphology,
probably due to strain. We investigate the influence of NdGaO3 substrates on
the limit of the ferromagnetic-metallic phase field in La1-xCaxMnO3, doping
with x=1% resolution. Films with x=0.40 show a metal-insulator transition, but
the ferromagnetic volume fraction is half the spin aligned value. Films with
x=0.41 are similar but the metal-insulator transition is not always seen. Films
with x=0.42, 0.43, 0.44, 0.45 are insulating, and the magnetization is
dramatically reduced. The observed phase boundary indicates where to search for
enhanced phase separation effects that may be exploited in thin films and
devices.
