Effects of Mg Doping on Microstructure and Dielectric and Ferroelectric Properties of Lead-Free NaBiTi6O14 Ceramics

The influence of Mg doping on a type of Na0.5Bi0.5TiO3 (NBT)-based ceramic, viz. NaBiTi6O14, has been investigated. NaBi(Ti1−xMgx)6Oy ceramics (x = 0.03, 0.06, 0.09, 0.12) were prepared by a traditional solid-phase method, and the influence of Mg doping on their microstructure, dielectric properties, and ferroelectric performance studied. Scanning electron microscopy (SEM) showed that the doped ceramics had clearer grain boundaries and more uniform grain size than the undoped ceramic. Mg doping enhanced the dielectric properties of the NaBiTi6O14 ceramic, with lower dielectric loss and higher dielectric constant. Z* plots showed that the NaBi(Ti1−xMgx)6Oy ceramics were a kind of dielectric. The activation energy of the ceramics was found to be 1.083 eV, 1.087 eV, 1.086 eV, and 0.861 eV, respectively, confirming their excellent dielectric performance. Ferroelectric hysteresis measurements showed that the NaBi(Ti1−xMgx)6O14−6x ceramics exhibited weak ferroelectric performance with 2Pr values of 0.079 μC cm−2 to 0.195 μC cm−2. The stable behavior of the doped ceramics may enable their application in high-temperature and high-frequency devices.