Thermally Initiated Reversal Modes in Infinite Periodic Ferromagnetic Wires

In finite ferromagnetic wires, the demagnetizing effects along the wire axis have a substantial influence on the reversal processes. By considering infinite wires, these effects are annihilated and only the sample dimensions, cross-sectional geometry, and material properties determine the magnetization reversal. The magnetization reversal is now initiated by small thermal fluctuations. With decreasing cross-sectional dimensions, three different reversal modes can be distinguished: reversal with (i) domain formation; (ii) vortex formation; and (iii) precessional switching combined with buckling. For different cross-sectional dimensions and lattice axes orientations, the 3-D magnetization dynamics and evolution of the different micromagnetic energy terms are investigated, resulting in a clear understanding of the reversal modes.