Effects of annealing and strain on La1-xCaxMnO3 thin films:: A phase diagram in the ferromagnetic region

Oriented, single phase thin films of La1-xCaxMnO3 have been deposited onto (100)-oriented LaAlO3 (0.1 < x < 0.5) substrates using the pulsed laser deposition technique. While for some compositions, the physical properties (transport and magnetization) of the as-grown films are higher than the bulk values, for other calcium contents the optimized properties are obtained only after annealing under oxygen. These data can be partly explained by changes in oxygen content resulting in cationic vacancies, and thus self-doping effects, accompanying structural changes, may be the cause of properties beyond the phase diagram. We propose a phase diagram for (La1-xCax)(1-y)square(y)MnO(3) (0.1 < x < 0.5) thin films. (C) 1999 American Institute of Physics. [S0003-6951(99)03136-8].