The XIX International Scientific Conference of Young Scientists and Specialists Dubna, Russia February 16-20, 2015 SYNTHESIS OF NON-AGGLOMERATED COBALT FERRITE NANOPARTICLES Sonja Jovanović,1,2 Matjaž Spreitzer,2 Danilo Suvorov2 1 Laboratory of Physics, Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia 2 Advanced Materials Department, Jožef Stefan Institute, Ljubljana, Slovenia Introduction Cobalt ferrite – CFO • • • • high coercivity moderate saturation magnetization large magnetic anisotropy large magnetostrictive coefficient Ferrimagnetic behavior Superparamagnetic behavior optics ferrofluids catalysis biomedicine sensors recording madia dcr=100 nm dsp=10 nm AIM preparation of superparamagnetic non-agglomerated CFO nanoparticles Synthesis of CFO NPs Co-precipitation Solvothermal synthesis Water/1-pentanol (1:5) solution of NaOH and Black precipitate Oleic acid T=180 oC, t=16h mixing Aq. solution of Co(NO)2∙6H2O and Fe(NO)3∙9H2O mixing 2h at RT Washing samples with n-hexane/ethanol Drying on air at RT Black precipitate Black powder Results – XRD and TEM Scale bar is 10 nm Results – TGA and FTIR 3400 cm-1 Stretching of hydroxide groups (moisture) 3007 cm-1 C-H stretching of =C-H group 2961 cm-1 Asymmetric stretching of –CH3 group 2925 cm-1 and 2855 cm-1 1642 cm-1 1547 cm-1 and 1421 cm-1 Asymmetric and symmetric stretching of –CH2 group H-O-H scissoring Asymmetric and symmetric stretching of –COOH group 1458 cm-1 –CH2 scissoring 1356 cm-1 In-plane O-H banding 1311 loss saturates C-O stretching Weight at 25 % cm-1 734 cm-1 -CH rocking vibration (at least four 590 cm-1 Stretching of metal ion at the tetrahedral A-site, MA↔O 2 - formation of a complete monolayer methylenes in the row) Δ = 126 cm-1 bridging bidentate – covalently bonded -COO- groups to the surface metal atoms Results – VSM COA = 0 - 0.20 M - ferrimagnetic behavior COA = 0.25 - 2 M - superparamagnetic behavior conclusions - gradual change of oleic acid concentration - Improved size and shape uniformity of CFO NPs - Preparation of hydrophobic, non-agglomerated NPs - Tuning of magnetic properties - Critical concentration - 0.25 M More information: S. Jovanović et al., J. Alloy Compd. 589 (2014) 271 - 277 S. Jovanović et al., J. Phys. Chem. C, 118 (2014) 13844 – 13856. THANK YOU!!!