X-ray photoemission study in Re0.7Ca0.3MnO3 epitaxial films

We have performed the x-ray photoemission experiments in the colossal magnetoresistive manganites Re0.7Ca0.3MnO3 with Re=La, Pr, and Nd in order to study the Re dependence of electronic structures in this system. The samples are epitaxial films grown on LaAlO3 substrates with pulsed laser deposition system. It is found that the binding energies of Mn 2p3/2 are 641.7 and 643.1 eV for La0.7Ca0.3MnO3 and Nd0.7Ca0.3MnO3, respectively. The shift of this energy level is related to the change in bond angle and/or bond length between Mn and oxygen. Moreover, two lines of O 1s core level are assigned as Mn–O (530 eV) and Re–O (533 eV). The intensity ratio of these two lines in Nd0.7Ca0.3MnO3 is different from those in La0.7Ca0.3MnO3 and Pr0.7Ca0.3MnO3, suggesting that the ion redistribution between Re–O and Mn–O sites occurs with the Re substitution in these films.