Solid State Science and Technology, Vol. 20, No 1 & 2 (2012) 28-34

ISSN 0128-7389






Ghazaleh Bahmanrokh1,* and Mansor Hashim1,2

1Physics Department, Faculty of Science, University Putra Malaysia,

43400 UPM, Serdang, Selangor, Malaysia

2Advance Materials and Nanotechnology Laboratory,

Institute of Advanced Technology, University Putra Malaysia,

43400 UPM, Serdang, Selangor, Malaysia


*Corresponding author:



Among many ferromagnetic materials cobalt nanoparticles with high coercivity and

small grain size are one of the potential candidates having application in high-density

storage media manufacturing. Magnetic cobalt nanoparticles have been synthesized via

microemulsion technique to control the shape and size of high quality magnetic

nanoparticles. In this technique, cetiltrimethylammonium bromide (CTAB) was added

as surfactant to control the particle size. The morphology and magnetic properties have

been characterized before and after annealing by X-ray diffraction, transmission

electron microscopy and vibrating sample magnetometer. The hysteresis measurement

of as prepared sample exhibits a coercivity of 27.26 Oe at room temperature. Annealing

the sample at 400 C enhance magnetic properties and change the crystal structure of

particles from hcp to fcc.

Keywords: cobalt; nanoparticles; microemulsion; coercivity



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