Atomistic spin model of single pulse toggle switching in Mn$_2$Ru$_x$Ga Heusler alloys

TL;DR

This paper presents an atomistic spin model that successfully simulates single femtosecond pulse toggle switching in Mn$_2$Ru$_x$Ga Heusler alloys, challenging previous assumptions about the necessity of element-specific demagnetization differences.

Contribution

The study introduces a quantitative atomistic model for toggle switching in Mn$_2$Ru$_x$Ga, showing switching is possible even with similar demagnetization rates of Mn sublattices, contrary to prior beliefs.

Findings

Model reproduces experimental magnetization dynamics.

Toggle switching occurs even with similar Mn sublattice demagnetization rates.

Challenges previous understanding of ferrimagnetic switching mechanisms.

Abstract

Single femtosecond pulse toggle switching of ferrimagnetic alloys is an essential building block for ultrafast spintronics. Very different element-specific demagnetization dynamics is believed to be a hard limit for switching in ferrimagnets. This suggests that ferrimagnets composed of two ions of different nature, such as rare earth transition metal alloys, are necessary for switching. However, experimental observation of toggle switching in Mn$_2$Ru$_x$Ga Heusler alloys, has contested this limit since Mn ions are of the same nature. To shed some light into this question, we present an atomistic spin model for the simulation of single pulse toggle switching of Mn$_2$Ru$_x$Ga. The magnetic parameters entering in our model are extracted from previous experimental observations. We show that our model is able to quantitatively reproduce measured magnetization dynamics of single pulse toggle switching. We demonstrate that differently to previous understanding toggle switching in Mn$_2$Ru$_x$Ga is possible even when both Mn sublattices demagnetization at very similar rate.