Anisotropy of Superparamagnetic Particles as Measured by Torque and Resonance

Abstract

Simple statistical reasoning has been applied to the case of an assembly of crystallographically aligned superparamagnetic particles at a given field and temperature. The apparent magnetocrystalline anisotropy as measured both by torque and resonance has been deduced for the cases of uniaxial and cubic anisotropies. Certain features of recent experimental results on precipitated cobalt particles can be explained, including the observation that, at high temperatures, the anisotropy measured by resonance is greater than that measured by torque.