Sašo Gyergyek (Author), Mihael Drofenik (Author), Darko Makovec (Author)

Abstract

Magnetic $CoFe_2O_4$ nanoparticles were synthesized by co-precipitation at 80 °C. This co-precipitation was achieved by the rapid addition of a strong base to an aqueous solution of cations. The investigation of the samples that were quenched at different times after the addition of the base, using transmission electron microscopy (TEM) coupled with energy-dispersive X-ray spectroscopy (EDXS) and X-ray powder diffractometry, revealed the formation of a Co-deficient amorphous phase and $Co(OH)_2$, which rapidly reacted to form small $CoFe_2O_4$ nanoparticles. The nanoparticles grew with the time of aging at elevated temperature. The colloidal suspensions of the nanoparticles were prepared in both an aqueous medium and in a non-polar organic medium, with the adsorption of citric acid and ricinoleic acid on the nanoparticles, respectively. The measurements of the room-temperature magnetization revealed the ferrimagnetic state of the $CoFe_2O_4$ nanoparticles, while their suspensions displayed superparamagnetic behaviour.

Keywords

cobalt ferrite;nanoparticles;co-precipitation;colloidal suspensions;magnetic properties;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
UDC: 546.732:620.3
COBISS: 28006183 Link will open in a new window
ISSN: 1318-0207
Views: 2146
Downloads: 74
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Other data

Secondary language: Slovenian
Secondary abstract: Magnetne nanodelce $CoFe_2O_4$ smo sintetizirali s soobarjanjem na temperaturi 80 °C. Soobarjanje smo dosegli s hitrim dodatkom močne baze k vodni raztopini kationov. Mehanizem nastanka nanodelcev $CoFe_2O_4$ smo študirali tako, da smo odvzeli vzorce pri različnih časovnih intervalih po dodatku baze in ustavili kemijske reakcije. Analize vzorcev s presevno elektronsko mikroskopijo (TEM) v kombinaciji z EDXS spektroskopijo in rentgensko praškovno difrakcijo (XRD) so pokazale nastanek amorfne Co deficitne faze in $Co(OH)_2$, ki hitro reagirata in nastanejo majhni $CoFe_2O_4$ nanodelci. Med staranjem na povišani temperaturi nanodelci rastejo. Koloidne suspenzije nanodelcev v vodnem in organskem ne- polarnem mediju smo pripravili z adsorpcijo citronske ozirom ricinolejske kisline. Meritve magnetnih lastnosti na sobni temperaturi so pokazale ferimagnetne lastnosti nanodelcev $CoFe_2O_4$ medtem, ko so suspenzije kazale superparamagnetno obnašanje.
Secondary keywords: kobaltov ferit;nanotehnologija;magnetne lastnosti;koprecipitacija;
URN: URN:NBN:SI
Type (COBISS): Scientific work
Pages: str. 488-496
Volume: ǂVol. ǂ61
Issue: ǂno. ǂ3
Chronology: 2014
ID: 10861000