Microstructural modifications of ferroelectric lead zirconate titanate ceramics due to bipolar electric fatigue

Fatigue in ferroelectric ceramics is the result of an intricate interplay of electrical, mechanical and electrochemical processes, each of which has been claimed responsible for fatigue. We present experimental results interrelating the different scales of the fatigue mechanism showing that all forms of fatigue occur. Electrochemical mechanisms lead to point defect agglomeration. The agglomerates are rendered visible as etch grooves in strongly etched surfaces by scanning electron microscopy. The overall length of the etch grooves strongly increases during cycling. Micro- and macrocracking were both observed and quantified using electron and optical microscopy. Their number similarly increases as a result of fatigue. Furthermore, a shrinkage of the unit cell volume was found by XRD.