KF添加Ba-Ti-O系強誘電体の比較 : BaTiO_3単結晶とBaTi_2O_5セラミックス

Temperature dependence of the dielectric constant on Ba_(1-x)K_xTiO_(3-x)F_x single crystals (0<x<0.13) was measured in a temperature range between 100 K and 450 K, and the relation of the phase transition temperatures vs. KF content was examined. The ferroelectric Curie-temperature T_C decreases monotonously from 390 K to 280 K with increasing x from 0 to 0.12, while the maximum value of the dielectric constant ε_(max) at T_C exhibits a peak around x=0.1. Furthermore, temperature dependence of the dielectric constant on Ba_(1-x)K_xTiO_(3-x)F_x ceramics (0<=x <=0.05) was measured in a temperature range between 100 K and 850 K. The ferroelectric Curie-temperature T_C steeply decreases by about 250 K by 1% KF-doping. The KF-doping effect on the ferroelectric properties was compared between BaTiO_3 and BaTi_2O_5