Stress-induced metallic behavior under magnetic field in Pr1-xCaxMnO3 (x=0.5 and 0.4) thin films (invited)

We have investigated the role of the stress induced by the presence of the substrate in thin films of colossal magnetoresistive manganites on structur al, resistive, and magnetic properties. Because of the strong coupling betw een the small structural distortions related to the charge ordering (CO) an d the resistive properties, the presence of the substrate prevents the full development of the charge ordering in Pr0.5Ca0.5MnO3, especially in the ve ry thin films. For thicker films, the CO state exists, but is not fully dev eloped. Correlatively, the magnetic field which is necessary to suppress th e CO is decreased drastically from 25 T to about 5 T on SrTiO3 substrates. We have also investigated the influence of the doping level by studying the case of Pr0.6Ca0.4MnO3. (C) 2001 American Institute of Physics.