材料期刊网

Lanthanum ferrites ceramics La_0.9A_0.1FeO₃ (A=Mg, Ca, Sr, Ba) have been prepared by solid state reaction. X-ray power diffraction analysis reveals that all samples are of pure perovskite structure with orthorhombic phase. Electrical conductivity and Seebeck coefficient have been measured in vacuum within the temperature range between room temperature and 800°C. The electrical conductivity shows semiconducting behavior. Temperature dependence of electrical conductivity indicates that adiabatic small-polaron hopping mechanism is dominant for their electric transportations. Seebeck coefficients are positive for samples, suggesting p-type conduction in the whole temperature range. The highest Seebeck coefficient is found to be 654 μV/K for La_0.9Mg_0.1 FeO₃. Except La_0.9Ba_0.1FeO₃, the electrical conductivity of La_0.9A _0.1FeO₃ increases with increasing atomic number of the A-site element, while Seebeck coefficient decreases.