Noncollinear spin structure in Dy-doped classical ferrimagnet

TL;DR

This paper demonstrates the induction of noncollinear, spiral-type spin structures in Dy-doped NiZAF thin films, revealing potential for chiral magnetic domains and topological textures in oxide-based spintronics.

Contribution

It provides experimental evidence and theoretical explanation for noncollinear spin structures induced by Dy doping in NiZAF, a novel approach in spinel ferrites.

Findings

Noncollinear spiral spin structure observed via XRMR.

Dzyaloshinskii-Moriya interaction attributed to Dy-induced strain.

Potential for chiral magnetic domains in oxide spintronics.

Abstract

Noncollinear spin structures have attracted tremendous attention because they offer a versatile platform for spin control and manipulation, essential in spintronics. Realizing noncollinearity in ferrimagnetic insulators is of particular interest as they can be potentially utilized in low-damping spintronics with tunable magnetic order. Within the spinel-ferrite family, Zn and Al-substituted nickel ferrite (NiZAF) has emerged as an excellent choice for low-damping spintronics. However, realizing noncollinearity in such systems remains challenging. Here, we present evidence of noncollinear spin structure in the NiZAF thin films induced by the rare earth Dy-doping, utilizing the soft x-ray spectroscopy methods such as magnetic circular dichroism and x-ray resonant magnetic reflectivity (XRMR). In particular, XRMR reveals a spiral-type spin structure, which is attributed to the Dzyaloshinskii-Moriya interaction, arising due to broken inversion symmetry by the Dy-induced local strain field as confirmed by our theoretical calculations. The realization of noncollinearity in the spinel-ferrite opens pathway to explore the possibility of chiral magnetic domains and topological spin textures exhibiting promise for oxide-based spintronics