Crystal growth and magnetic property of orthorhombic RMnO3 (R=Sm–Ho) perovskites by mild hydrothermal synthesis

We have successfully grown several RMnO3 (R=Sm–Ho) crystals by mild hydrothermal treatment of mixtures prepared from rare earth oxides, k-birnessite gel and KOH. Crystal growth of rare earth manganate perovskites was sensitive to alkalinity, temperature, filling fraction, nature of the rare earth ion and composition of initial reaction mixture. The structure of DyMnO3 by single-crystal X-ray diffraction (XRD) and of the others by Rietveld refinement indicate that these perovskites adopt orthorhombic symmetry, which is in contrast to the usual observation of hexagonal structure in RMnO3 with heavier rare earth ions prepared under normal or high-pressure conditions. The variable temperature magnetization studies of these crystals show magnetic ordering at low temperatures and are in agreement with earlier reports.