PMN-PSMNT ceramics fabricated using the twin-crystal mixed co-firing method

(1- w )[Pb(Mg 1/3 Nb 2/3 ) 0.67 Ti 0.33 O 3 ]- w [Pb 1 − 1.5 x Sm x (Mg 1/3 Nb 2/3 ) y Ti 1− y O 3 ] ((1- w )PMN- w PSMN-PT) piezoelectric ceramics were prepared using the newly proposed twin-crystal mixed co-firing method in which two pre-sintered precursor powders were mixed and co-fired with designated ratios ( w  = 0.3, 0.4, 0.5, 0.6). X-ray diffraction results show that all the samples presented a pure perovskite structure. The grains were closely packed and the average size was ~ 5.18 µm from the observations of scanning electron microscopy images, giving the high density of ceramics to be 97.8% of the theoretical one. The piezoelectric, dielectric, and ferroelectric properties of the ceramic samples have been investigated systematically. It was found that the performance of ceramics was significantly enhanced when compared to the ceramics fabricated using the conventional one-step approach. Outstanding piezoelectric coefficient d 33 of 1103 pC/N and relative dielectric permittivity ε r of 9154 could be achieved for the ceramics with w  = 0.5.