Topochemical Reduction of YMnO 3 into a Composite Structure

Topochemical modification methods for solids have shown great potential in generating metastable structures inaccessible through classical synthetic routes. Here, we present the enhanced topotactic reduction of the multiferroic compound YMnO . At moderate temperature in ammonia flow, the most reduced YMnO (δ = 0.5) phase could be stabilized. XRD, PND, and HREM results show that phase separation occurs into two intimately intergrown layered sublattices with nominal compositions [YMn O ] and [YMn O ] containing versatile Mn coordinations. The former sublattice shows original AA stacking between Mn layers, while AB stacking in the latter results from oxygen removal from the parent YMnO crystal structure.