Thermal coercivity mechanism in Fe nanoribbons and stripes

We investigate the influence of thermally activated process on coercivity values of long Fe nanostripes. By means of the Lagrangian multiplier technique and the micromagnetic approach, we evaluate energy barriers separating the two magnetization states of long Fe nanostripes, varying their width from 30 to 250 nm. As the width of nanostripes decreases, the reversal time, evaluated through the Arrhenius-Neel law, becomes comparable to the measurement time scale (characteristic for typical magnetometer) for fields below the values obtained through zero-temperature micromagnetic approach. We found appreciable variation of the coercivity due to thermal activation for stripe widths below 100 nm.