A FRACTAL ANALYSIS ON DOMAIN RELATED ELECTRIC-FIELD-INDUCED ACOUSTIC-EMISSION IN FERROELECTRIC CERAMICS

The electric field induced acoustic emission (AE) in ferroelectric cer amics under bipolar electric fields has been studied. From the AE even t rate and the AE signal amplitude distribution, it is assumed that th ere are two origins of the field induced AE in the ferroelectric ceram ics: domain reorientation related deformation and piezoelectric deform ation without domain reorientation. The fractal dimension (m) in the f ield induced AE signal amplitude distribution of the ferroelectric cer amic is found to be m = 1 for the domain reorientation related deforma tion. The fractal dimension of m = 2.8 is observed for the piezoelectr ic deformation unrelated to domain reorientation after domain reorient ation is completed. It is shown that the fractal dimension of the AE c aused by the domain reorientation related deformation is lower than th at of the AE generated by the piezoelectric deformation unrelated to d omain reorientation at high electric fields.