Magnetocaloric effect and size-dependent study of the magnetic properties of cobalt ferrite nanoparticles prepared by solvothermal synthesis

✍ Scribed by Vázquez-Vázquez, C. ;Lovelle, M. ;Mateo, C. ;López-Quintela, M. A. ;Buján-Núñez, M. C. ;Serantes, D. ;Baldomir, D. ;Rivas, J.

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 520 KB
• Volume: 205
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200778128

✦ Synopsis

Abstract

Cobalt ferrite (CoFe~2~O~4~) nanoparticles from 2 nm to 15 nm were synthesized using a solvothermal procedure. In this non‐aqueous method, acetophenone was used as solvent and the particle size was controlled by changing the reaction temperature from 120 °C to 180 ºC. Nanoparticles show good crystallinity and uniformity above 140 °C, as determined by X‐ray diffraction and transmission electron microscopy. Magnetic measurements indicate superparamagnetic behaviour. Zero‐field‐cooling (ZFC) dc‐magnetisation experiments at 100 Oe show blocking temperatures ranging from 215 K to more than 305 K. Saturation magnetisation increases with particle size and a small decrease is observed when increasing the temperature. The magnetocaloric effect shown by these cobalt ferrite nanoparticles is reasonably high for nanomaterials. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)