Atomistic spin model of single pulse toggle switching in Mn2RuxGa Heusler alloys

Abstract

Single femtosecond-pulse toggle switching of ferrimagnetic alloys is an essential building block for ultrafast spintronics. It is believed that for switching to occur in these ferrimagnets, the individual sublattices must have very different (element-specific) demagnetization dynamics. This suggests that ferrimagnets composed of two different elements, such as rare-earth transition-metal alloys, are necessary for switching. However, experimental observations of toggle switching in the Heusler alloy Mn2Ru xGa, which has two crystallographically nonequivalent Mn sublattices with antiparallel aligned moments, have questioned these assertions. To shed some light on this question, we present an atomistic spin model for the simulation of single pulse toggle switching of Mn2Ru xGa. The magnetic parameters entering our model are extracted from previous experimental observations. We show that our model is able to quantitatively reproduce the experimentally measured magnetization dynamics of single pulse toggle switching. We demonstrate that toggle switching in Mn2Ru xGa is possible even when both Mn sublattices demagnetize at very similar rates, in contradiction to the previous hypothesis about the importance of element-specific demagnetization rates in this process.