Effect of Poling Electric Field and Temperature Change on the Dielectric Anomalies of Relaxor Ferroelectric Strontium-Barium-Niobate Single Crystals

摘要

The dielectric properties of the uniaxial relaxor ferroelectric SrxBa1-xNb2O6 with x = 0.75 were investigated along the polar [001] direction as a function of temperature. The capacitance maximum showed the frequency dispersion commonly observed in relaxors. Additional weak dielectric anomalies were observed in the paraelectric phase; they were only seen during the heating process and disappeared upon subsequent cooling. These were attributed to the existence of large polar clusters strongly pinned at defects and/or to random fields and their metastable characters. Aligning the ferroelectric domains along the polar axis at room temperature removed the high-temperature dielectric anomalies. The dependences of the capacitance and the dielectric maximum temperature on the magnitude of the poling field were investigated.