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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Laboratory for Materials and Structures, IIR,Tokyo Institute of Technology Professor Masaki Azuma, PhD Student Masayuki Fukuda and Department of Materials and Earth Sciences, Nonmetallic Inorganic Materials, Technical University of Darmstadt, Professor Jürgen Rödel
“Enhanced Spontaneous Polarization by V4+ Substitution in a Lead-Free Perovskite CaMnTi2O6”
ACS Publications 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+.