Effect of Ho doping on piezoelectric properties of BCZT ceramics

Lead-free (Ba0.99Ca0.01)(Ti0.98Zr0.02)O3 (BCZT) + x mol% Ho (x = 0–0.6) ceramics were prepared using solid-state reaction technique. High piezoelectric coefficient of d33 = 330 pC/N and planar electromechanical coupling factor of kp = 40% were obtained at x = 0.2%. Furthermore, greatly enhanced temperature stability of the piezoelectric properties was obtained in the temperature range from 20 to 100 °C, in which the Ho doped BCZT ceramics exhibited pure tetragonal phase. With the increase of Ho content, the orthorhombic–tetragonal phase transition shifted towards low temperature, while Curie temperature (Tc) remained at about 120 °C. The results indicate that Ho doped BCZT ceramics could be promising candidate as lead-free piezoelectric materials.