La_(0.7)Pr_(0.3)MnO_(3) ceramic: An electron-doped colossal magnetoresistive manganite

摘要

We report a study on the synthesis, electrical transport, and magnetic properties of Pr-doped LaMnO_(3) ceramic material. We have found that La_(1-x)Pr_(x)MnO_(3+δ)(x=0.3) synthesized using solid-state reaction shows semiconductor behavior, and no colossal magnetoresistance (CMR) effect; while it shows CMR behavior when it is annealed in a flowing argon at certain temperature (about 873 K), which suggests that La_(0.7)Pr_(0.3)MnO_(3+δ) has been transferred to La_(0.7)Pr_(0.3)MnO_(3). The x-ray photoemission spectroscopy reveals that Pr ions are in a mixed-valence state of Pr~(4+) and Pr~(3+) in this compound. Therefore, La_(1-x)Pr_(x)MnO_(3)(x=0.3) could be an electron-doped CMR manganite.