AC poling-induced giant piezoelectricity and high mechanical quality factor in [001] PMN-PZT hard single crystals

Recently, a novel poling technique is introduced for the piezoelectric single crystals (SCs) which uses an AC electric field, opposite to the common practice of DC poling (DCP). However, AC poling (ACP) has mostly been used for soft (Generation II) SCs. This study reports ACP induced high piezoelectricity in an Mn-doped [001] Pb(Mg,Nb)O₃–Pb(Zr,Ti)O₃ (PMN-PZT) hard SC (Generation III). The ACP [001] PMN-PZT hard SC showed a giant piezoelectric charge coefficient (d₃₃) of >2000 pC/N, a high mechanical quality factor (Q_m) of >300, an increase in the dielectric constant (∼250%), and rhombohedral to tetragonal phase transition temperature (T_R-T ≈ 136 °C) with a 26% increase in the coercive field (E_c). The piezoforce microscopy images of the ACP SC showed smaller domains with a narrow domain size distribution, which may result in higher piezoelectric properties. The single crystal which shows the highest d₃₃ with a high value of Q_m of 266, was poled using ACP conditions of 1 Hz and 600 s with 600 cycles. The ACP SC also showed excellent fatigue endurance with low fatigue in the remanent polarization (P_r), E_c, and internal bias field (E_in).