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

Compositional effects on the structural, magnetic and transport properties was investigated on a series of La1-xCaxMnO3 films deposited on LaAlO3 by pulsed laser ablation. X-ray diffraction, DC resistivity and magnetometer measurements showed a thin film phase diagram that is somewhat different from that of the bulk, showing transport and magnetization properties higher in the as-grown films than in the bulk for some compositions. Optimized metal-to-insulator transition temperature and Curie temperature were realized by oxygen annealing. This was attributed to the strains induced by the substrate and the change in oxygen stoichiometry leading to cation vacancies due to annealing.