02133nas a2200253   4500008004100000245009100041210006900132260000800201300001300209490000800222520132700230653001301557653001901570653005201589653002601641653002301667100001701690700001601707700001201723700001501735700002001750700001901770856009001789       2017                        eng d00aMagnetic studies of SiO<inf>2</inf> coated CoFe<inf>2</inf>O<inf>4</inf> nanoparticles0 aMagnetic studies of SiOinf2inf coated CoFeinf2infOinf4inf nanopa  cNOV  a 683-6900 v4413 aOleic acid capped CoFe2O4 nanoparticles which exhibit a high coercivity of ∼9.47 kOe at room temperature were coated with a robust coating of SiO2. We have used chemical synthesis method to obtain SiO2 coated CoFe2O4 nanoparticles with different weight percentages of CoFe2O4 in SiO2 (1.5, 3.1 and 4.8 wt.%). The morphological investigation of the coated nanoparticles by transmission electron microscopy shows that the particles are spherical with average size ∼160 nm. Infrared spectroscopy reveals that oleic acid capping on the surface of CoFe2O4 nanoparticles is retained after silica coating process. The complete coating of SiO2 on CoFe2O4 nanoparticles is confirmed by X-ray photoelectron spectroscopy as there is no signature of cobalt or iron ions on the surface. Magnetic measurements show that coercivity of SiO2 coated CoFe2O4 particles remains more or less unaffected as in CoFe2O4 nanoparticles at room temperature. In addition, the temperature dependent magnetic measurements show that at 5 K the CoFe2O4 and SiO2 coated 1.5 wt.% CoFe2O4 samples exhibit a very high value of coercivity (∼20 kOe) which is more than twice as compared to room temperature coercivity value (∼9.47 kOe). We conclude that silica coating in our study does not significantly affect the coercivity of CoFe2O4 nanoparticles.10aCoatings10acoercive force10aHigh Resolution Transmission Elctron Microscopy10ainfrared spectroscopy10aMagnetic materials1 aLimaye, M.V.1 aSingh, S.B.1 aDas, R.1 aPoddar, P.1 aAbyaneh, M., K.1 aKulkarni, S.K.  uhttps://library.ncl.res.in/content/magnetic-studies-sio2-coated-cofe2o4-nanoparticles