# Observation of Topological Hall Effect and Signature of Room Temperature Antiskyrmions in Mn-Ni-Ga D2d Heusler magnets

## TL;DR

This study reports the observation of room-temperature antiskyrmions in Mn-Ni-Ga Heusler alloys, revealing a large topological Hall effect and potential for racetrack memory applications.

## Contribution

It demonstrates the stabilization of antiskyrmions at high temperatures in Mn-Ni-Ga alloys, linking D2d symmetry to topological spin structures and their Hall effects.

## Key findings

- Large topological Hall effect observed beyond room temperature.
- Antiskyrmions stabilized up to 550 K via composition tuning.
- Micromagnetic simulations confirm stabilization mechanisms.

## Abstract

Topologically stable nontrivial spin structures, such as skyrmions and antiskyrmions, display a large topological Hall effect owing to their quantized topological charge. Here, we present the finding of a large topological Hall effect beyond room temperature in the tetragonal phase of a Mn-Ni-Ga based ferrimagnetic Heusler shape memory alloy system. The origin of the field induced topological phase, which is also evidenced by the appearance of dips in the ac-susceptibility measurements, is attributed to the presence of magnetic antiskyrmions driven by D2d symmetry of the inverse Heusler tetragonal phase. Detailed micromagnetic simulations asserts that the antiskyrmionic phase is stabilized as a result of interplay among inhomogeneous Dzyaloshinskii-Moriya interaction, the Heisenberg exchange, and the magnetic anisotropy energy. The robustness of the present result is demonstrated by stabilizing the antiskyrmion hosting tetragonal phase up to a temperature as high as 550 K by marginally varying the chemical composition, thereby driving us a step closer to the realization of ferrimagnetic antiskyrmion based racetrack memory.