Comment on "Magnetoresistance and phase composition of La-Sn-Mn-O systems"

Abstract

In a published paper by Li et al. [Phys. Rev. B 60, 10284 (1999)] the transport properties and phase composition of the manganites La1-xSnxMnO3+δ (x=0.1-0.5) are studied. The authors analyze their results assuming the existence of two phases: a perovskite LaMnO3+δ and a pyrochlore (La0.5Sn0.5)2Mn2O7. We consider that they misinterpret the x-ray diffraction data and we conclude that the manganites La1-xSnxMnO3+δ are in fact a multiphase material composed by LaMnO3+δ, La2Sn2O7, Mn3O4, and SnO2. The magnetic transition observed by Mössbauer experiments around 65 K attributed by Li et al. to that of the (La0.5Sn0.5)2Mn2O7 pyrochlore phase would correspond to that of the paramagnetic-ferrimagnetic one of Fe-doped Mn3O4.