Thermal switching field distribution of a single domain particle for field-dependent attempt frequency

We present an analytical derivation of the switching field distribution (SFD) at finite temperature for a single domain particle from the Néel-Brown model in the presence of a linearly swept magnetic field. By considering the field dependence of the attempt frequency f 0 in the rate equation, we find enhancement of coercivity compared to models using constant f 0. The contribution of thermal fluctuations to the standard deviation of the switching field H C derived here reaches values of 10 H C. Considering this contribution, which has been neglected in previous work, is important for the correct interpretation of measurements of switching field distributions. © 2012 American Institute of Physics.