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The XIX International Scientific Conference of Young Scientists and Specialists
Dubna, Russia
February 16-20, 2015
Sonja Jovanović,1,2
Matjaž Spreitzer,2 Danilo Suvorov2
1 Laboratory of Physics, Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia2 Advanced Materials Department, Jožef Stefan Institute, Ljubljana, Slovenia
SYNTHESIS OF NON-AGGLOMERATED COBALT FERRITE NANOPARTICLES
• high coercivity• moderate saturation magnetization• large magnetic anisotropy• large magnetostrictive coefficient
Cobalt ferrite – CFO
Ferrimagnetic behavior
dcr=100 nm dsp=10 nm
Superparamagnetic behavior
AIM
preparation of superparamagnetic non-agglomerated CFO nanoparticles
optics ferrofluids catalysis
biomedicine sensors recording madia
Introduction
Water/1-pentanol (1:5) solution of NaOH and
Co-precipitation
Washing samples with n-hexane/ethanol
Drying on air at RT
Black powder
T=180 oC, t=16h
Black precipitate
Solvothermal synthesis
Aq. solution of Co(NO)2∙6H2O and Fe(NO)3∙9H2O
Black precipitate
mixing
mixing 2h at RT
Oleic acid
Synthesis of CFO NPs
Tefl
on-l
ined
, sta
inle
ss-s
teel
aut
ocla
ve
Results – TGA and FTIR
Weight loss saturates at 25 %
- formation of a complete monolayer
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 Asymmetric and symmetric stretching of –CH2 group
1642 cm-1 H-O-H scissoring
1547 cm-1 and 1421 cm-1 Asymmetric and symmetric stretching of –COOH group
1458 cm-1 –CH2 scissoring
1356 cm-1 In-plane O-H banding
1311 cm-1 C-O stretching
734 cm-1 -CH2 rocking vibration (at least four methylenes in the row)
590 cm-1 Stretching of metal ion at the tetrahedral A-site, MA↔O
bridging bidentate –
covalently bonded
-COO- groups to the surface metal atoms
Δ = 126 cm-1
COA = 0.25 - 2 M
- superparamagnetic behavior
COA = 0 - 0.20 M
- ferrimagnetic behavior
Results – VSM
- 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
conclusions
S. Jovanović et al., J. Alloy Compd. 589 (2014) 271 - 277 S. Jovanović et al., J. Phys. Chem. C, 118 (2014) 13844 – 13856.
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