Stability of Magnetic Domains With Notches in Permalloy Nanowires

Thermal stability of magnetic domains in ferromagnetic Permalloy nanowires is investigated by means of micromagnetic calculation with finite temperature. The magnetic domains, initially placed between two domain walls pinned at either artificial notches or edge roughness, are examined to be collapsed or not with thermal fluctuation. The stable domain size is revealed to be linearly dependent on the wire width, with different proportionality for different domain wall types-either transverse or vortex wall, irrespective to the wall alignment-either parallel or antiparallel to each other. The vortex walls provide regular stable domain size insensitive to the wire edge roughness, whereas the stability with the transverse walls is much influenced.