Defects and Degradation of BaTiO3 Codoped with Dy and Mn

High-temperature electrical conductivities and leakage current behaviors of Dy-doped, and Dy and Mn codoped BaTiO3 were investigated as a function of Ba/Ti ratio. Dy-doped BaTiO3 specimens showed higher leakage currents under a continuously applied dc field stress at 150°C than undoped BaTiO3. The highest initial leakage current was observed with Ba(Ti0.98Dy0.02)O2.99. The equilibrium electrical conductivity of Ba(Ti0.985Dy0.01Mn0.005)O3 is proportional to Po2-1/4 in the n-type region, and Po2+1/6 in the p-type region. The conductivity behavior of (Ba0.99Dy0.01)(Ti0.995Mn0.005)O3 is similar to the previous results on the donor-doped BaTiO3. Regardless of the occupation site of Dy ions, BaTiO3 specimens codoped with Dy and Mn showed lower leakage currents, and the leakage current of (Ba0.99Dy0.01)(Ti0.995Mn0.005)O3 was below 10-10 A under the same conditions.