Electric Field Induced-Strain Behavior of Single Lead-Free KNBT Piezoelectric Fiber

In this work, electric field-induced strain properties of sodium potassium bismuth titanate single fiber were investigated as a function of temperature. The results show that the normalized strain increases significantly with increasing temperature and reaches the maximum value of 315 pm/V at 160°C. Meanwhile, the negative strain decreases with increasing temperature, and then almost disappears in the vicinity of depolarization temperature. The temperature-dependent X-ray diffraction patterns, Raman spectra, polarization-electric field hysteresis loops, and the associated current-electric field curves show that the giant strain may be attributed to the antiferroelectric-ferroelectric phase transition.