Electrical Properties of Lead‐Free Na 1/2 Bi 1/2 TiO 3 Relaxor Ferroelectric Ceramics Doped with Hafnium or Zirconium

Ferroelectric (Na 1/2 Bi 1/2 )TiO 3 and its various solid solutions have been drawing special attention as a new candidate for their lead‐based counterparts. In this study, therefore, hafnium‐ or zirconium‐doped grain‐oriented (Na 1/2 Bi 1/2 )TiO 3 ceramics with <001> pc orientation were fabricated by templated grain growth method using anisotropically shaped SrTiO 3 template particles. These molten salt synthesized SrTiO 3 platelets were tape cast with calcined (Na 1/2 Bi 1/2 )TiO 3 powders, and then sintered at 1200°C for 6 h. Texture fractions up to 70% have been obtained. Unipolar strains up to >0.25% were measured. Doped ceramics showed a “relaxor‐like” ferroelectric behavior. A broad dielectric peak with a slim hysteresis loop was present for hafnium‐ or zirconium‐doped samples. Electrostrictive coefficient of hafnium‐doped (Na 1/2 Bi 1/2 )TiO 3 ceramics were found to be 0.032 m 4 /C 2 , which is much larger than that of PMN ‐based electrostrictive materials. Electromechanical properties of hafnium‐ and zirconium‐doped (Na 1/2 Bi 1/2 )TiO 3 ceramics under electric bias were studied as well.