Magneto-elastic enhancement of sublattice interactions in RMn7O12

The quadruple perovskite manganites provide a fruitful playground to explore the interplay between charge, orbital and spin degrees of freedom on multiple sublattices, producing exotic phases of fundamental scientific and technological interest. Across the monoclinic A3+Mn7O12 family, competing descriptions of magnetic order have been put forward and ascribed to the same characteristic magnetic intensities. Such discrepancies have emerged due to an inherent difficulty in differentiating competing models against magnetic diffraction alone. Using symmetry arguments we have established that a strong magneto-elastic coupling scheme, as evidenced in the lattice parameters, can support only one of the proposed magnetic models.We propose a neutron powder diffraction experiment on PrMn7O12 to confirm our hypothesis. Secondly, we aim to solve the ground state magnetic structure, likely elucidating the role of orbital instabilities in mediating magnetism across the wider family.