Effects of Mn doping on dielectric properties of Mg-doped BaTiO3

The motion of oxygen vacancy as a defect complex and the effects of Mn addition on the dielectric relaxation in the Ba(Ti1-x-yMgxMny)O3-delta system have been studied in the frequency range of 25-10(6) Hz at various temperatures. The dielectric constants (k) of 0.5 mol % Mg-doped BaTiO3 rapidly decreased with increasing frequency at < 1 kHz and 200 degrees C. There was a slight decrease in k observed for the BaTiO3 codoped with Mg and Mn and no change in k for singly Mn-doped BaTiO3. Loss peaks (tan delta) shifted to lower frequencies as the Mn content was increased, and the peak moved to higher frequencies with increasing temperature. Activation energies for the relaxation process of the Ba(Ti0.995-yMg0.005Mny)O3-delta system for y=0, 0.005, and 0.01 at 150-300 degrees C were 0.47, 0.69, and 0.62 eV, respectively, and at higher temperatures of 400-500 degrees C were 1.08, 1.28, and 1.47 eV for each corresponding composition. (c) 2006 American Institute of Physics.