Fig. 2: The dielectric and piezoelectric property evolutions for multi-elements and single-element doped KNN ceramics.
From: The mechanism for the enhanced piezoelectricity in multi-elements doped (K,Na)NbO3 ceramics

a The dielectric behaviour of KNN-Bi,Sb,Zr (multi-element doped KNN) ceramic over a temperature range of 130–700 K. b The dielectric and c piezoelectric properties of the multi-elements and single-element doped KNN ceramics over a temperature range of 120–300 K. d The temperature dependence of the tetragonal phase fraction and piezoelectric coefficients d33 over a temperature range of 298–490 K for KNN-Bi,Sb,Zr ceramic.