Laboratory for Materials and Structures, IIR,Tokyo Institute of Technology Professor  Masaki Azuma, Visiting Professor Masaaki Matsuda (Neutron Scattering Division, Oak Ridge National Laboratory)
“Stabilized Charge, Spin, and Orbital Ordering by the 6s² Lone Pair in Bi_0.5Pb_0.5MnO₃“
ACS Publications doi.org/10.1021/acs.inorgchem.0c01748

<Abstract>
Bi and Pb ions with charge degree of freedom depending on 6s² and 6s⁰ electronic configurations were combined with the Mn ion in a perovskite oxide. Comprehensive theoretical and experimental investigations revealed the Bi³⁺_0.5Pb²⁺_0.5Mn³⁺_0.5Mn⁴⁺_0.5O₃ charge ordered state with CE-type spin and dz² orbital orderings as observed in La_0.5Ca_0.5MnO₃, Nd_0.5Sr_0.5MnO₃, and Bi_0.5Sr_0.5MnO₃. The charge and orbital orderings were preserved above 500 K owing to the stereochemical activity of Bi³⁺ and Pb²⁺ ions which stabilized the structural distortion.