Magneto-orbital ordering in the divalent A-site quadruple perovskite manganites AMn7O12(A=Sr, Cd, and Pb)

Journal article

Through analysis of variable temperature neutron powder diffraction data, we present solutions for the magnetic structures of SrMn₇O₁₂, CdMn₇O₁₂, and PbMn₇O₁₂ in all long-range ordered phases. The three compounds were found to have magnetic structures analogous to that reported for CaMn₇O₁₂. They all feature a higher temperature lock-in phase with commensurate magneto-orbital coupling, and a delocked, multi-k magnetic ground state where incommensurate magneto-orbital coupling gives rise to a constant-moment magnetic helix with modulated spin helicity. CdMn₇O₁₂ represents a special case in which the orbital modulation is commensurate with the crystal lattice and involves stacking of fully and partially polarized orbital states. Our results provide a robust confirmation of the phenomenological model for magneto-orbital coupling previously presented for CaMn₇O₁₂. Furthermore, we show that the model is universal to the A quadruple perovskite manganites synthesised to date, and that it is tunable by selection of the A-site ionic radius.

Authors: Johnson, R; Khalyavin, D; Manuel, P; Radaelli, P; Glazkova, I

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Physical Society
• Journal: Physical Review B
• Volume: 96
• Issue: 5
• Pages: 054448
• Publication date: 2017-08-17
• Acceptance date: 2017-08-18
• DOI: 10.1103/PhysRevB.96.054448
• EISSN: 2469-9969
• ISSN: 2469-9950
• Keywords: Jahn-Teller effect; antiferromagnetism; magnetism