Contributions of domain wall motion to complex electromechanical coefficients of 0.62Pb(Mg1/3Nb2/3)O3-0.38PbTiO3 crystals

The loss behavior of 0.62Pb(Mg1/3Nb2/3)O-3-0.38PbTiO(3) (PMN-38%PT) ferroelectric single crystal poled along [001](c) was investigated. It was found that the complex electromechanical coefficients and loss factors change dramatically at the coercive field E-c around 250 V/mm, representing the intrinsic switching barrier. Since the energy loss is related to the domain wall motion, the imaginary parts of the electromechanical coefficients can be used to study the degree of domain wall motions in relaxor-based ferroelectric single crystals. Experimental results indicate that for this system, domain wall motion contributes significantly to the imaginary parts of electromechanical coefficients. In addition, [001](c) poled PMN-38%PT single crystals have much larger mechanical loss factor compared to that of conventional single crystal like LiNbO3. This phenomenon is proved to be closely related to 90 degrees domain wall motion in this crystal system.