Magnetization behavior of nanometer-scale iron particles

摘要: The magnetic properties (magnetic moment, shape anisotropy, switching field, and distribution) of nanometer-scale ferromagnetic iron particles are investigated by measuring magnetization curves for different particle orientations. measured fields indicate that curling accounts the reversal at ``zero'' temperatures an exchange length, ${\ensuremath{\lambda}}_{\mathrm{ex}}$=2.6 nm, is deduced. A phenomenological model describing temperature dependence field used to estimate activation volume, ${v}_{A}=270 {\mathrm{nm}}^{3}$. This small compared volume may explain experimental fact cannot be described thermal over average single energy barrier.