A large and anisotropic enhancement of the mechanical quality factor in ternary relaxor-PbTiO3 single crystals

Enhancing the mechanical quality factor, Qm, in ferroelectrics is one of the most critical issues for high-power devices, such as therapeutic ultrasonic transducers, large-displacement actuators, and high-frequency transducers. Although previous results have indicated that Qm could be improved through acceptor doping, the mechanism behind this effect is still a mystery, and there have been few reports on the optimization of energy loss in ultrahigh piezoelectric materials such as relaxor-PbTiO3 (PT) single crystals. In this work, we investigate the energy loss associated with various vibration modes in Mn-doped Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT:Mn) single crystals and compare with their undoped PIN–PMN–PT counterpart. We find that Q15, Q24, and Q33 in PIN–PMN–PT:Mn, respectively, undergo 160%, 100%, and 80% enhancements, thus demonstrating very large extrinsic contributions with unusual anisotropies in the Qm enhancement. Such a strong anisotropy is strongly interlinked with the orientation of the internal bias Ei and the charged domain walls. Our results provide some fundamental understanding of domain-engineered ferroelectric materials and materials-by-design for high-performance low-loss devices.