[19a-B303-1~10] 1.6 Ultrasonics

[19a-B303-10] Poling Temperature Optimization of Bi₄Ti₃O₁₂/SrTiO₃

〇MAKIKO KOBAYASHI¹, TOMOYA YAMAMOTO¹, SHOHEI NOZAWA¹ (1.Kumamoto Univ.)

Keywords:ultrasonic transducer, high temperature, lead free

Poling temperature of Bi₄Ti₃O₁₂ (BiT)/SrTiO₃ (ST), which was made by ferroelectric BiT powders and ST sol-gel solution, was investigated. BiT/ST samples were poled at RT and 700℃, respectively. Ultrasonic response of each sample was measured in pulse-echo mode with heating by a hotplate up to 500℃. As a result, at 500℃, both signal amplitude and SNR of the sample poled at RT were higher than those of the sample poled at 700℃. It was caused by poling difficulty of BiT around Curie temperature of BiT, because dielectric constant of BiT became highest at Curie temperature whereas dielectric constant of ST was constant.