Magnetic properties and energy absorption of CoFe2O4 nanoparticles for magnetic hyperthermia

TL;DR

This study investigates the magnetic and energy absorption properties of CoFe2O4 nanoparticles, highlighting how particle size and magnetic anisotropy influence their effectiveness in magnetic hyperthermia applications.

Contribution

It provides new insights into how nanoparticle size and anisotropy affect power absorption efficiency in magnetic hyperthermia.

Findings

Blocking temperatures range from 180 to 320 K.

High coercive fields observed at low temperatures.

SPA values up to 98 W/g for 12 nm particles.

Abstract

We have studied the magnetic and power absorption properties of three samples of CoFe2O4 nanoparticles with sizes from 5 to 12 nm prepared by thermal decomposition of Fe (acac)3 and Co(acac)2 at high temperatures. The blocking temperatures TB estimated from magnetization M(T) curves spanned the range 180 < TB < 320 K, reflecting the large magnetocrystalline anisotropy of these nanoparticles. Accordingly, high coercive fields HC \approx 1.4 - 1.7 T were observed at low temperatures. Specific Power Absorption (SPA) experiments carried out in ac magnetic fields indicated that, besides particle volume, the effective magnetic anisotropy is a key parameter determining the absorption efficiency. SPA values as high as 98 W/g were obtained for nanoparticles with average size of \approx12 nm.