Correlation Between Resistance Degradation and Thermally Stimulated Depolarization Current in Acceptor (Mg)‐Doped BaTiO ₃ Submicrometer Fine‐Grain Ceramics

Abstract

Thermally stimulated depolarization current (TSDC) of acceptor (Mg)‐doped BaTiO 3 ceramics was analyzed for submicrometer fine grain specimens. For a fixed condition of polarization field ( E P ) and polarization time ( t P ), the TSDC associated with an oxygen vacancy relaxation showed two peaks with relaxation temperatures ( T m ) under low polarization temperature ( T P ) conditions. It is inferred that the TSDC peak of the lower T m is due to the relaxation of a distributed space charge within a grain and has a short relaxation time constant (τ 0 ), and the higher T m is due to the long‐range relaxation across grain boundaries with a larger time constant, τ 0 . The onset condition for resistance degradation can be correlated with the breaking point of T P , at which the TSDC peak changes from in‐grain relaxation to across‐grain boundary relaxation. The breaking point of T P and the time to degradation systematically decreased with the increase of acceptor concentration. Such behavior can be correlated with the decrease of T P , T m , τ 0 , and little change of activation energy of relaxation, which is due to the increase of concentration .