tailieunhanh - Báo cáo hóa học: " Synthesis and Magnetic Properties of Maghemite (c-Fe2O3) Short-Nanotubes"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Synthesis and Magnetic Properties of Maghemite (c-Fe2O3) Short-Nanotubes | Nanoscale Res Lett 2010 5 1474-1479 DOI s11671-010-9664-4 NANO EXPRESS Synthesis and Magnetic Properties of Maghemite c-Fe2O3 Short-Nanotubes W. Wu X. H. Xiao S. F. Zhang T. C. Peng J. Zhou F. Ren C. Z. Jiang Received 26 March 2010 Accepted 3 June 2010 Published online 17 June 2010 The Author s 2010. This article is published with open access at Abstract We report a rational synthesis of maghemite y-Fe2O3 short-nanotubes SNTs by a convenient hydrothermal method and subsequent annealing process. The structure shape and magnetic properties of the SNTs were investigated. Room-temperature and low-temperature magnetic measurements show that the as-fabricated y-Fe2O3 SNTs are ferromagnetic and its coercivity is nonzero when the temperature above blocking temperature TB . The hysteresis loop was operated to show that the magnetic properties of y-Fe2O3 SNTs are strongly influenced by the morphology of the crystal. The unique magnetic behaviors were interpreted by the competition of the demagnetization energy of quasi-one-dimensional nanostructures and the magnetocrystalline anisotropy energy of particles in SNTs. Keywords Short-nanotubes y-Fe2O3 Magnetic properties Introduction In recent years the assembled nanostructures of magnetic iron oxide materials have attracted widespread interest W. Wu C. Z. Jiang Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education Wuhan University Wuhan 430072 People s Republic of China e-mail czjiang@ W. Wu X. H. Xiao S. F. Zhang T. C. Peng J. Zhou F. Ren C. Z. Jiang Center for Electronic Microscopy and School of Physics and Technology Wuhan University Wuhan 430072 People s Republic of China 0 Springer because of their diverse applications such as magnetic fluids data storage catalyst and bionanotechnology 1-3 . One-dimensional 1D nanostructures are very appealing owing to many unique physical and chemical properties based on their high intrinsic anisotropy and surface activity 4 5