(BA, SR)TIO3 SYSTEM UNDER DC-BIAS FIELD .1. IMPROVEMENT ON THE THERMOSTABILITY OF PYROELECTRIC RESPONSE BY ZR-SUBSTITUTION

(Ba, Sr)TiO3 (BST) is being actively investigated as a prime candidate material for thermal imaging sensor that utilizes the dielectric bolo meter (DB) mode. However, strong temperature-dependent pyroelectric pr operties of BST severely limit its widespread applications. In the pre sent study, we have attempted to improve the thermostability of pyroel ectric response by narrowing the temperature intervals between the thr ee consecutive rhombohedral-orthorhombic-tetragonal-cubic phase transi tions. For this purpose, we have partially substituted Zr ions for Ti ions in the B-site of perovskite structure. It was observed that the t hree pyroelectric peaks associated with the structural phase transitio ns coalesced together at near room temperature, exhibiting a broad pyr oelectric response at higher Zr concentrations (greater than or equal to 10 at.% Zr). It was shown that the broadness of pyroelectric respon se under the DC-bias field was closely correlated with the broadness o f pyroelectric response in the absence of DC-bias field. Therefore, th e thermostability of pyroelectric response under the DC-bias field was also significantly improved by the Zr-substitution.