Characterization of magnesium doped lanthanum orthoniobate synthesized by molten salt route

Molten salt synthesis method has been used to prepare the single phase magnesium doped lanthanum orthoniobate. The phase composition has been checked by X-ray diffraction method and the microstructure studies have been performed by scanning electron microscopy. The high temperature properties of the material have been investigated by thermogravimetry and electrochemical impedance spectroscopy. A dependence between sample total conductivity and temperature has been found supporting the thesis that there is strong correlation between apparent activation energy of conductivity and structural phase transition at ~500 °C. It has been also shown that the conductivity of magnesium doped lanthanum orthoniobate synthesized by the molten salt route reaches values of ~1 mS/cm at 720 °C in wet hydrogen.