Fast Atomistic Spin Dynamics (FASD): A Scalable Approach for Time-Dependent Magnetic Phenomena in Nanostructures

A methodology to perform Atomistic Spin Dynamics (ASD) calculations on magnetic nanometric structures in highly reduced times compared with standard approaches is proposed. To this aim, a scaling technique (ST) is implemented within the ASD framework by determining the appropriate time scaling factor, an approach referred to as Fast Atomistic Spin Dynamics (FASD). The quality of the FASD scheme is demonstrated by comparisons with micromagnetic simulations of well-known domain wall (DW) motion phenomena. After establishing its reliability, the FASD approach is applied to study DW motion in diameter-modulated ferromagnetic nanowires. The results offer two main advantages: (i) they enable the use of the FASD tool to perform simulation studies of time-dependent magnetic phenomena in systems consisting of many atoms in reduced times, and (ii) they reveal novel behaviors and phenomena related to DW movement in diameter-modulated samples of current technological interest.