Effect of Pr3+ doping on relaxation behavior and strain response of PHT-based piezoelectric ceramics

Heterovalent ion doping has influenced the further development of piezoelectric applications. Pr3+ doping in relaxor ferroelectrics is rarely focused on piezoelectric performance enhancement. 0.51Pb(Ni1/3Nb2/3)O3-0.49Pb(Hf0.3Ti0.7)O3 (PNN-49PHT) ceramics with Pr3+ doping ceramics were designed and fabricated by a two-step precursor method. Excellent dielectric diffusion coefficient (γ) of 1.96 was achieved at the low Pr3+ doping concentration of 0.2%. Increased relaxation enhanced the nanoscale domains formation, resulting in a giant strain response (d*33) of 1400pm/V at 10kV/cm, and a total strain (Stol) of 0.27% at 20kV/cm. Structural refinement unveiled that the high piezoelectricity originated from the mainly substitution of Pr3+ for Pb2+ at the A-site, inducing lattice distortion and phase transitions. Local domain switching and long-range ordered destruction were investigated by piezoresponse force microscopy (PFM) and Scanning Electron Microscopy (SEM). These findings contribute to the advancement of piezoelectric devices and provide valuable insights for the design and optimization of high-performance piezoelectric ceramics.