Squeezing N\'eel-type Magnetic Modulations by Enhanced Dzyaloshinskii-Moriya interaction of $4d$ Electrons

TL;DR

This study reveals that polar non-centrosymmetric magnets with 4d electrons exhibit robust Nel-type skyrmion phases with sub-10 nm periodicity, driven by enhanced Dzyaloshinskii-Moriya interactions and strong spin-orbit coupling.

Contribution

It demonstrates the stabilization of highly compressed Nel-type magnetic modulations in 4d electron systems due to enhanced Dzyaloshinskii-Moriya interactions and spin-orbit coupling.

Findings

Nel-type modulations are robust against magnetic fields up to 2 T.

Enhanced spin-orbit coupling leads to sub-10 nm periodic phases.

Non-centrosymmetric 4d and 5d magnets are promising for hosting compressed skyrmions.

Abstract

In polar magnets, such as GaV$_4$S$_8$, GaV$_4$Se$_8$ and VOSe$_2$O$_5$, modulated magnetic phases namely the cycloidal and the N\'eel-type skyrmion lattice states were identified over extended temperature ranges, even down to zero Kelvin. Our combined small-angle neutron scattering and magnetization study shows the robustness of the N\'eel-type magnetic modulations also against magnetic fields up to 2 T in the polar GaMo$_4$S$_8$. In addition to the large upper critical field, enhanced spin-orbit coupling produces a variety of modulated phases with sub-10 nm periodicity and a peculiar distribution of the magnetic modulation vectors. Thus, our work demonstrates that non-centrosymmetric magnets with $4d$ and $5d$ electron systems are ideal candidates to host highly compressed magnetic spirals and skyrmions.