DYNAMIC EFFECTS OF DIPOLAR INTERACTIONS ON THE SPECIFIC LOSS POWER OF Mn 0 . 7 Zn 0 . 3 Fe 2 O 4

In this work, isothermal magnetization and initial dc susceptibility of spheroidal, nearly monodisperse Mn0.7Zn0.3Fe2O4 nanoparticles (typical diameter: 20 nm) prepared by a hydrothermal route have been measured between 10 and 300 K. The high-temperature inverse magnetic susceptibility was always found to follow a linearly temperature dependence. The deviation from the standard superparamagnetic behavior is related to dipolar interaction among nanoparticles. The results are well explained using interacting superparamagnetic model, which is basically a mean field theory. As a consequence, the dipolar interaction affected the specific loss power of Mn0.7Zn0.3Fe2O4