Dramatic pressure-driven enhancement of bulk skyrmion stability

TL;DR

Applying moderate pressure to Cu2OSeO3 significantly enlarges the temperature and field range where skyrmion lattices are stable, revealing a new route to enhance their thermodynamic stability for potential spintronic applications.

Contribution

Demonstrated that pressure tuning can substantially increase skyrmion stability in bulk materials, extending the skyrmion phase region via electronic structure modifications.

Findings

Pressure enlarges skyrmion stability region in Cu2OSeO3.

Change in anisotropy drives skyrmion phase expansion.

Theoretical extension confirms anisotropy as key control parameter.

Abstract

The recent discovery of magnetic skyrmion lattices initiated a surge of interest in the scientific community. Several novel phenomena have been shown to emerge from the interaction of conducting electrons with the skyrmion lattice, such as a topological Hall-effect and a spin-transfer torque at ultra-low current densities. In the insulating compound Cu2OSeO3, magneto-electric coupling enables control of the skyrmion lattice via electric fields, promising a dissipation-less route towards novel spintronic devices. One of the outstanding fundamental issues is related to the thermodynamic stability of the skyrmion lattice. To date, the skyrmion lattice in bulk materials has been found only in a narrow temperature region just below the order-disorder transition. If this narrow stability is unavoidable, it would severely limit applications. Here we present the discovery that applying just moderate pressure on Cu2OSeO3 substantially increases the absolute size of the skyrmion pocket. This insight demonstrates directly that tuning the electronic structure can lead to a significant enhancement of the skyrmion lattice stability. We interpret the discovery by extending the previously employed Ginzburg-Landau approach and conclude that change in the anisotropy is the main driver for control of the size of the skyrmion pocket. This realization provides an important guide for tuning the properties of future skyrmion hosting materials.