Comparative study of photo-induced effect on the charge-ordered state of Pr0.65Ca0.35MnO3 in powder and thin films

Recent progress on the survey of photo-induced effect in Pr0.65Ca0.35MnO3 i s reported with respect to the electron paramagnetic resonance (EPR) and X- ray diffraction (XRD). In the powder samples, a photo-induced effect is rep orted in the charge-ordered (CO) phase associated with the canted antiferro magnetic (AF) spin order. First, the paramagnetic resonance, which is dimin ished at the onset of the AF spin order, revives with the near-infrared las er irradiation of hv = 1.17 eV. Second, XRD indicates that the photo-induce d paramagnetic resonance is associated with the melting of the CO formed by the alternation of the ionic valence of Mn. The thin films of Pr0.65Ca0.35 MnO3 prepared by the sol-gel method exhibit magnetic transition at low temp erature. However, the ground slate of the discussed thin film is not accomp anied by the CO-state. (C) 2000 Elsevier Science B.V. All rights reserved.