Enhanced Spontaneous Polarization by V4+ Substitution in a Lead-Free Perovskite CaMnTi2O6

• Published in: Inorganic chemistry 2020-08, Vol.59 (16), p.11749-11756
• Main Authors: Fukuda, Masayuki, Nishikubo, Takumi, Pan, Zhao, Sakai, Yuki, Zhang, Mao-Hua, Kawaguchi, Shogo, Yu, Hongwu, Okimoto, Yoichi, Koshihara, Shin-ya, Itoh, Mitsuru, Rödel, Jürgen, Azuma, Masaki
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.0c01697

Spontaneous polarization (P s) of novel order–disorder type lead-free ferroelectric CaMnTi2O6 was successfully enhanced by partial V4+ substitution for Ti4+. A synchrotron X-ray diffraction study revealed that the polar displacement of octahedrally coordinated (Ti, V) in CaMn­(Ti1–x V x )2O6 (0 ≤ x ≤ 0.4) increases with V4+ substitution having Jahn–Teller activity owing to the d1 electronic configuration. Our magnetic study suggested the presence of antisite disorder between Ca2+ and square planar coordinated Mn2+ associated with Mn–V intermetallic charge transfer for x ≥ 0.4, resulting in decreases in spontaneous polarization and the ferroelectric–paraelectric transition temperature. This is the first report on the enhanced polarization owing to the Jahn–Teller distortion of V4+ without stereochemical Pb2+ or Bi3+.