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Synthesis and characterization of magnetic nano particles
Author(s) -
Qiu XingPing
Publication year - 2000
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.20000180607
Subject(s) - chemistry , superparamagnetism , ionic strength , nanoparticle , magnetic nanoparticles , precipitation , saturation (graph theory) , ionic bonding , ion , atmospheric temperature range , chemical engineering , analytical chemistry (journal) , magnetization , inorganic chemistry , magnetic field , chromatography , thermodynamics , aqueous solution , organic chemistry , mathematics , quantum mechanics , combinatorics , meteorology , engineering , physics
Magnetic nanoparticles with average diameter in the range of 6.4–8.3 nm have been synthesized by a chemical co‐precipitation of Fe(II) and Fe(III) salts in 1.5 M NH 4 OH solution. The size of the magnetic particles is dependent on both temperature and the ionic strength of the iron ion solutions. The magnetic particles formed at higher temperature or lower ionic strength were slightly larger man those formed at lower temperature or higher ionic strength respectively. In spite of the different reaction conditions, all the resultant nanoparticles are nearly spherical and have a similar crystalline structure. At 300 K, such prepared nanoparticles are superparamagnetic. The saturation magnetizations for 7.8 and 6.4 nm particles are 71 and 63 emu/g respectively, which are only ∼ 20–30% less than the saturation magnetization (90 emu/ g) of bulk Fe 3 O 4 . Our results indicated mat a control of the reaction conditions could be used to tailor the size of magnetic nanoparticles in free precipitation.