Synthesis and Magnetic Properties of CoFe2O4 Nano Powder Prepared by Mechanical Milling

Recently, spinel ferrites have been intensively studied because of their wide range of applications as high-density information storage system, ferrofluid, magnetocaloric refrigeration, medical diagnostics, magnetic resonance imaging enhancement and gas sensors. Amongst various types of spinel ferrites, cobalt ferrite CoFe2O4 has attracted considerable attention due to their large magnetocrystalline anisotropy, high coercivity, moderate saturation magnetization, chemical stability and mechanical hardness [1]. Various techniques have been developed to prepare nanosized cobalt ferrite particles such as co-precipitation [2],sol-gel [3], hydrothermal [4] and mechanical alloying [5]. Mechanical alloying/activation techniques lend itself very advantageous for the synthesis of various alloys and oxide compounds including electroceramic materials. Of course, measures should be taken regarding the introduction of impurities during milling process. Successful synthesis of CoFe2O4 nanoparticles with a molar ratio of Co to -Fe2O3 1:1 was reported using mechanical alloying by R.Sani et al [6]. We report here the phase evolution and magnetic properties of CoFe2O4 nanoparticles prepared by mechanical alloying technique using metallic cobalt and hematite powder as the initial raw materials with a molar ratio of Co to -Fe2O3 1:2 in ambient air atmosphere