La2Mo2O9在低氧分压条件下的电导率及热膨胀测试

The electrical conductivity and thermal expansion of La2Mo2O9 under low oxygen partial pressure were studied with the help of thermoelectric power and dilatometric measurements, respectively. The ionic conduction of La2Mo2O9 was predominant with the electronic transference number less than 0.05 above an oxygen partial pressure of about Po2=10^-7 Pa at 700℃, and below this pressure the electronic conduction became obvious. The defect reaction and small polaron hopping among molybdenum sites were proposed to explain the electronic conduction. Accompanying the phase transition, there was a sharp increase of thermal expansion, which became more serious under low oxygen partial pressure. The substitution of lanthanum by neodymium led to the increase of electrical conductivity but the decrease of phase stability.