Crystal and electronic structures ferroelectric perfomance of Bi₄Si₃O₁₂ added Bi_4-xSm_xTi₃O₁₂ ferroelectric materials

Abstract

Bismuth layer structure ferroelectric (BLSF) have been widely investigated as capacitors of nonvolatile ferroelectric random access memories. Among the BLSF, we focused on Bi_4-xSm_xTi₃O₁₂ (BST) and Bi₄Si₃O₁₂-added ones (BSTS) in this work, and examined their ferroelectric performance and crystal and electronic structures. In order to clarify these structures, we measured synchrotron X-ray diffraction patterns of the materials and analyzed the patterns with Rietveld method and MEM. As a result, it was found that both BST and BSTS had single phases and their phases were monoclinic (S. G. :B1a1) at room temperature and tetragonal (S.G. :I4/mmm) at 1000 K.