Study of magnetic structure and electrical-transport properties of La1−yBayMn1−xFexO3 (y = 0.15, 0.40) perovskite manganites

An O 2p itinerant-electron model for magnetic oxides, which is similar to the O 2p hole-carrier model proposed by Alexandrov et al. [Phys. Rev. Lett. 96 (2006) 117003], was used to explain the magnetic and electrical-transport properties of two series of samples with the nominal composition La1−yBayMn1−xFexO3 (0.00 ≤ x ≤ 0.20; y = 0.15, 0.40). The samples were prepared using the sol-gel method, and X-ray diffraction patterns showed that all samples were single-phase ABO3 perovskite structures. The magnetic and electrical-transport properties of the samples were characterized. Interesting phenomena were observed for the magnetic moment, μobs, of the samples at 10 K: μobs of the samples with y = 0.15 decreased approximately linearly when the Fe-doping level was increased from zero to x = 0.2. However, there was a characteristic Fe-doping level, xC = 0.10, for the samples with y = 0.40. When x ≤ xC, μobs decreased very slowly; when x > xC, μobs decreased rapidly. These interesting phenomena suggest that the samples had a canted magnetic structure, but the cant angle of the samples with y = 0.15 was smaller than that of the samples with y = 0.40. These magnetic structures were further confirmed by the electrical-transport properties of the samples.