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

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

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科学技術創成研究院フロンティア材料研究所 東正樹教授、福田真幸博士課程2年、ダルムシュタット工科大学 Jürgen Rödel教授との共著論文
“Enhanced Spontaneous Polarization by V4+ Substitution in a Lead-Free Perovskite CaMnTi2O6”
が、ACS Publicationsに掲載されました。doi.org/10.1021/acs.inorgchem.0c01697

<Abstract>
Spontaneous polarization (Ps) 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–xVx)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+.