Thin films of perovskite manganite La0.7Ca0.3MnO3 were grown
epitaxially on various substrates by either the pulsed laser deposition method
or laser molecular beam epitaxy. The substrates change both the volume and
symmetry of the unit cell of the films. It is revealed that the symmetry as
well as the volume of the unit cell have strong influence on the
metal-insulator transition temperature and the size of magnetoresistance.Comment: 6 pages, 3 figure