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: One-Pot Reaction and Subsequent Annealing to Synthesis Hollow Spherical Magnetite and Maghemite Nanocages | Nanoscale Res Lett 2009 4 926-931 DOI s11671-009-9342-6 NANO EXPRESS One-Pot Reaction and Subsequent Annealing to Synthesis Hollow Spherical Magnetite and Maghemite Nanocages Wei Wu Xiangheng Xiao Shaofeng Zhang Hang Li Xiaodong Zhou Changzhong Jiang Received 24 April 2009 Accepted 5 May 2009 Published online 22 May 2009 to the authors 2009 Abstract Water-soluble hollow spherical magnetite Fe3O4 nanocages ca. 100 nm with high saturation magnetization are prepared in a one-pot reaction by sol-gel method and subsequent annealing to synthesise the maghemite y-Fe2O3 nanocages with similar nanostructures. The nanocages have been investigated by powder X-ray diffraction XRD transmission electron microscope TEM high-resolution transmission electron microscope HRTEM and superconducting quantum interference device SQUID . The results indicated that glutamic acid played an important role in the formation of the cage-like nanostructures. Keywords Magnetite Maghemite Sol-gel growth Nanocages Introduction Magnetic nanoparticles are of great interest to researchers for their wide range a board of applications including magnetic fluid data storage catalyst and biotechnology owing to their unique magnetic properties such as W. Wu C. Jiang H Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education Wuhan University 430072 Wuhan People s Republic of China e-mail czjiang@ W. Wu X. Xiao S. Zhang H. Li X. Zhou C. Jiang Department of Physics Wuhan University 430072 Wuhan People s Republic of China W. Wu X. Xiao C. Jiang Center of Electron Microscopy Wuhan University 430072 Wuhan People s Republic of China superparamagnetic low Curie temperature and high coercivity high susceptibility. 1 . Currently magnetic nanoparticles are used in important biological applications mainly including magnetic bioseparation and detection of biological entities such as cell protein nucleic acids enzyme bacterials and virus. 2 3 . To this end magnetic iron .