Structure, transport properties, and electronic structure of epitaxial thin films La 0.9 Sn 0.1 MnO 3 and La 0.9 Ca 0.1 MnO 3 have been experimentally studied. According to the Hall-effect measurement, La 0.9 Sn 0.1 MnO 3 is an n-type conductor in the metallic state due to the substitution of Sn for La. X-ray photoelectron spectroscopy spectra revealed a shift of the Fermi level and the Mn ionic core level of La 0.9 Sn 0.1 MnO 3 in comparison with La 0.9 Ca 0.1 MnO 3. The difference between the Mn-2p spectra of La 0.9 Sn 0.1 MnO 3 and La 0.9 Ca 0.1 MnO 3 implies that Mn ions in the former are at a Mn 2ϩ /Mn 3ϩ mixed-valence state, which is significantly different from the divalent-element-doped manganese oxides, where the Mn ions are in the mixed-valence state of Mn 3ϩ /Mn 4ϩ .

No abstract

No abstract

Magnetic and dielectric properties of a polycrystalline GaFeO 3 sample prepared by a solid-state reaction have been investigated. A ferrimagnetic phase transition T N of the material was identified at a temperature of 225 K. An anomaly on the permittivity as a function of temperature has been observed near its magnetic transition point T N , which could be induced by the magnetoelectric coupling between its electric and magnetic orders. At low temperature, T < T N , the permittivity variation ε depends on magnetization M and shows clearly a linear relationship between ε and M 2 , which indicates that a dielectric and magnetic correlation exists in the compound. Furthermore, its dielectric relaxation process is discussed in the temperature interval of 77-300 K.