The XIX International Scientific Conference of Young Scientists and Specialists Dubna, Russia February 16-20, 2015 Sonja Jovanović, 1,2 Matjaž Spreitzer,

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

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ined

, sta

inle

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teel

aut

ocla

ve

Scale bar is 10 nm

Results – XRD and TEM

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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