Self-heating effects of the surface oxidized FeCo nanoparticles colloid   under alternating magnetic field
  To evaluate the self-heating effects of FeCo magnetic nanoparticles, the surface oxidized FeCo nanoparticles were synthesized by co-precipitation method with the reduction reaction without any post treatments. As-synthesized FeCo nanoparticles exhibited the mean diameter of about 39 nm with the oxidized shell thickness of about 4-5 nm. The saturation magnetization and coercivity were obtained 172 emu/g and 268 Oe at 300 K, respectively. The heat elevation of the FeCo magnetic colloid was measured under alternating magnetic fields of 76, 102, and 127 Oe with selectable frequencies of 190, 250 and 355 kHz. The heat temperature increased up to about 45 oC from initial temperature of 24 oC under 127 Oe and 355 kHz, which the specific absorption exhibited about 35.7 W/g. 
Jinu Kim, Baekil Nam and Ki Hyeon Kim
cond-mat.mes-hall cond-mat.mtrl-sci