The elastic and piezoelectric properties of tungsten bronze ferroelectric crystals (Sr_(0.7)Ba_(0.3)_2NaNb_5O_(15) and (Sr_(0.3)Ba_(0.7)_2NaNb_5O_(15)

摘要

The elastic and piezoelectric constants of tungsten bronze ferroelectric crystals (Sr_(0.7)Ba_(0.3)NaNb_5O_(15) (SBNN70) and (Sr_(0.3)Ba_(0.7))_2NaNb_5O_(15 (SBNN30) are determined by using the ultrasonic and resonance methods. The measured results show that these single crystals have larger dielectric constant and good piezoelectric property compared to other known lead-free perovskite ferroelectric crystals. The measurements show that the SBNN70 has larger dielectric and piezoelectric constants than SBNN30 since the former is near the morphotropic phase boundary composition. Our results confirmed that the SBNN single-crystal system is another good candidate as lead-free piezoelectric and dielectric materials.