Temperature-Dependent Electrical Properties of 0.94Bi(0.5)Na(0.5)TiO(3)-0.06BaTiO(3) Ceramics

Temperature-dependent electrical properties of lead-free 0.94Bi(0.5)Na(0.5)TiO(3)-0.06BaTiO(3) (BNT-BT) ceramics were investigated. Below 100 degrees C, this rhombohedral-tetragonal morphotropic phase-boundary composition shows dominant ferroelectric order with typical ferroelectric polarization-electric field (P(E)) loop and butterfly bipolar strain-electric (S(E)) curve. Antiferroelectric order tends to prevail when temperature reaches about 100 degrees C, characterized by a pinched P(E) loop and altered bipolar S(E) butterfly. Near the ferroelectric-antiferroelectric transition temperature, the composition shows a giant bipolar and unipolar strain of 0.40% and 0.42%, respectively. The highest value of maximum strain divided by the applied field (i.e., S-max/E-max) reaches 700 pm/V at 100 degrees C. With a further increase of temperature to 200 degrees C, a slight decrease of the strain is observed. Especially, it is found that the hysteresis of the unipolar S(E) curve decreases with increasing temperature. These results may be helpful for further understanding and thus designing new BNT-based lead-free piezoelectric systems.