Sintering and electrical properties of La-modified (Na0.52K0.45Li0.03)1−3xLax(Nb0.88Sb0.09Ta0.03)O3 lead-free ceramics

Abstract (Na 0.52 K 0.45 Li 0.03 ) 1−3 x La x (Nb 0.88 Sb 0.09 Ta 0.03 )O 3 (NKLL x NST) lead-free ceramics were prepared by normal sintering and their dielectric and piezoelectric properties were investigated. The X-ray methods indicate that the NKLL x NST ceramics with x ≤0.003 present a pure perovskite phase at room temperature. The bulk density of NKLL x NST ceramics increases with proper amount of La 2 O 3 contents, and reaches its highest value of 4.544 g/cm 3 with the addition of 0.3 mol% La 2 O 3 . At x =0.003, remnant polarization P r , piezoelectric constant d 33 and planar mode electromechanical coupling factor k p of NKLL x NST ceramics reach the highest values of 37.80 μC/cm 2 , 346 pC/N and 40%, respectively, exhibiting excellent “soft” piezoelectric characteristics, demonstrating a tremendous potential of the compositions studied for device applications.