title: Dramatic changes in the magnetic coupling mechanism for La-doped CaMnO3.
abstract: The exchange interactions in polycrystalline samples of Ca1-xLaxMnO3 (0.00< or =x< or =0.05) are studied by means of Raman scattering and electron paramagnetic resonance. Dramatic reductions in the spin-phonon interactions and magnetic correlations are observed for La doping levels as small as approximately 2%-3%. These results show that the charge carriers play an important role in the overall exchange coupling in the electron-doped manganites, even at very low doping levels.
authors.affiliation: Instituto de Física "Gleb Wataghin," UNICAMP, 13083-970, Campinas-SP, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Granado
authors.forename: N O
authors.initials: NO
authors.lastname: Moreno
authors.forename: H
authors.initials: H
authors.lastname: Martinho
authors.forename: A
authors.initials: A
authors.lastname: García
authors.forename: J A
authors.initials: JA
authors.lastname: Sanjurjo
authors.forename: I
authors.initials: I
authors.lastname: Torriani
authors.forename: C
authors.initials: C
authors.lastname: Rettori
authors.forename: J J
authors.initials: JJ
authors.lastname: Neumeier
authors.forename: S B
authors.initials: SB
authors.lastname: Oseroff