Microstructure and magnetization of single-crystal perovskite manganites nanowires prepared by hydrothermal method

Single-crystal La-0.5(Ba, Sr)(0.5)MnO3 nanowires were synthesized by a hydrothermal method at low reaction temperature. X-ray diffraction study shows all samples are single phase with cubic perovskite structure. Transmission electron microscopy images reveal that the samples consist of a large quantity of wirelike nanostructures with typical lengths in the range of several to several tens of micrometers. Each nanowire has a uniform width along its entire length, the typical widths of the nanowires are in the range of 30-150nm for La0.5Ba0.5Mn0.5 and 50-400nm for La0.5Sr0.5MnO3. High-resolution transmission electron microscopy shows that the nanowires grow along [110]; their surfaces are clean, very regular, and without any sheathed amorphous phase. The magnetization behavior of La0.5Ba0.5MnO3 is different from that of La0.5Sr0.5MnO3. The former sample shows the typical magnetization behavior of an ordinary ferromagnet, however the latter sample exhibits a spin freezing behavior. (C) 2002 Elsevier Science B.V. All rights reserved.