The dielectric properties of Mn-dopedPb(Fe_(2/3)W_(1/3))_(1-x)Mn_xO_3 (x = 0, 0.001, 0.003, and0.005) in the temperature range 200-600 K were investigated.Two sets of dielectric peaks, located at 200-350 K and 350-600K, were observed. The intensity of the dielectric permittivityand loss factor peaks for both relaxations decreased with theincrease in the Mn content and no peak occurred when x = 0.005.Nonlinear current-voltage (I-V) behavior was observed in thesamples containing less than 0.005Mn. The activation energyvalues for the relaxations at 200-350 K and at 350-600 K werearound 0.42 and 0.56 eV, respectively. The direct currentconduction activation energies were around 0.41 eV. Nitrogenannealing eliminated the relaxation peaks at 200-350 K whileoxygen annealing enhanced them. Both annealing eliminated thedielectric peaks at 350-600 K. The nonlinear I-V characteristictended to vanish either after the oxygen or the nitrogenannealing treatments. Relaxation mechanisms are proposed anddiscussed. It is suggested that the relaxation at 200-350 K isrelated to electron hole while the relaxation at 350-600 K isattributed to microstructure-dependent space-charge polarization.
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