Effect of Cr₂O₃ modification on dielectric, ferroelectric and field-induced strain properties of 0.18Pb(Mg_1/3Nb_2/3)O₃–0.82Pb(Zr_0.49Ti_0.51)O₃ ceramics

A systematic investigation was performed to study the effect of Cr₂O₃ on dielectric, ferroelectric and field-induced strain properties of 0.18Pb(Mg_1/3Nb_2/3)O₃–0.82Pb(Zr_0.49Ti_0.51)O₃ (0.18PMN–0.82PZT) ceramics. The PMNZT/xCr₂O₃ (with x = 0, 0.1, 0.15, 0.2, 0.25, 0.30, 0.50 wt%) ceramics were prepared by solid state reaction and sintering process. Dielectric properties of the as-prepared ceramics were characterized, wherein the maximum dielectric constant (ɛ _m) presents an increasing trend when x < 0.15, followed by a down-trend with an abrupt increase at x = 0.50. The temperature of maximum dielectric constant (T _m) appears to display a slight change from 297 °C (x = 0.50) to 310 °C (x = 0.30). At 1 kHz, the sample with composition of x = 0.15 has the largest room temperature dielectric constant ɛ _r of 1599 and maximum dielectric constant ɛ _m of 25813 at T _m, while the sample with composition of x = 0.3 possess the maximum dielectric relaxor factor of γ = 1.93. The remnant polarization gradually decreased from 37.3 to 23.10 μC/cm² with increasing Cr₂O₃ content. Meanwhile, compared with pure 0.18PMN–0.82PZT, the coercive field (E _c) of the 0.18PMN–0.82PZT+xCr₂O₃ ceramics are found to be significantly improved when x > 0.10. Furthermore, the field-induced strain of 0.18PMN–0.82PZT+xCr₂O₃ ceramics appeared to be lower than that of pure 0.18PMN–0.82PZT. However, an up-trend is observable in the field-induced strain of 0.18PMN–0.82PZT+xCr₂O₃ ceramics with increasing Cr₂O₃ content up to x = 0.15, which corresponds to a peak value of 0.158%.