We present the first in-depth study of the nuclear andmagnetic structures of the fully lithiated LiFe_xMn_(1-x)PO4 solid solutionsas well as the partially delithiated Li_(1-x)JFe_xMn_(1-x)PO4 series usingneutron powder diffraction. By using a weak oxidizing solution that onlyoxidizes Fe~(2+), we find that lithium can be removed from these olivines ina stepwise manner. Representational analysis was performed on theobserved magnetic reflections and found that the lithiated solidsolutions order in the magnetic space group Prima', which is identicalto triphylite (LiFePO4). We report that, even when removing 20 ofthe lithium from the hcp lattice, the magnetic structure changes andmultiple magnetic contributions are needed to fully encompass theobserved magnetic order. We find that the partially delithiated x = 0.2and 0.3 have a magnetic structure P2_1'/nll, and when x surpasses 0.3, the magnetic structure changes to P2_12_12_1. We give a detailedreport on the effect of delithiation on magnetic order, bond distances/angles, and the super- and supersuperexchange interactions inthe material. The symmetries of the magnetic order of these solid solutions are then discussed with regard to their potential asferrotoroidic candidates.
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