Spontaneous interstitial (anti)merons in D$_{2d}$ symmetric Mn-Pt(Pd)-Sn-In system

TL;DR

This paper reports the discovery of spontaneous (anti)merons within helical stripes in a D$_{2d}$ symmetric Mn-Pt(Pd)-Sn-In system, demonstrating potential for skyrmion Hall effect-free magnetic track applications.

Contribution

It provides the first observation of spontaneous (anti)merons stabilized in a D$_{2d}$ symmetric system with Lorentz TEM evidence, highlighting their formation mechanism and potential for topological magnetic devices.

Findings

Spontaneous stabilization of (anti)meron pairs at critical In concentration.

(Anti)merons exhibit constrained drift along helical stripes.

System enables skyrmion Hall effect-free magnetic motion.

Abstract

Interstitial topological objects, such as skyrmions, within a natural 1-D helix are predicted to be free from ambiguous 'skyrmion Hall effect'. The helical ambience precipitate an additional potential that counteract the Magnus force arising from the gyrotropic motion of skyrmion. Here, we present the observation of $\pm$ $\frac{1}{2}$ topological charge objects (anti)merons within the 1-D helical stripes in D$_{2d}$ symmetric Mn$_{1.4}$Pt$_{0.9}$Pd$_{0.1}$Sn$_{1-x}$In$_{x}$ system. With the help of Lorentz transmission electron microscopy study we demonstrate that the pair-wise meron and antimeron chains can be spontaneously stabilized for a critical In concentration in the system. The exchange frustration induced proportionate fragmentation of the magnetic moment in the in-plane and easy-axis directions acts as a basic ingredient for the formation of (anti)merons within the helical stripe. A constrained drift motion of (anti)merons along the stripe makes this system an ideal platform for the realization of skyrmion Hall free track motion. Moreover, the observation of (anti)merons in addition to the skyrmion and antiskyrmion in D$_{2d}$ materials makes them a suitable horizon for zoo of topology.