3D magnetic configuration of ferrimagnetic multilayers with competing interactions visualized by soft X-ray vector tomography

Abstract

Full control of magnetic properties in exchange coupled systems requires a good understanding of 3D magnetic configuration with lateral and in-depth resolution. Here we show results from a soft X-ray tomographic reconstruction which allow determining, solely from the experimental data, a detailed description of the vector magnetic configuration of a ferrimagnetic Gd₁₂Co₈₈/Nd₁₇Co₈₃/Gd₂₄Co₇₆ trilayer with engineered competing anisotropy, exchange and magnetostatic interactions at different depths. The trilayer displays chevron patterns with a distorted closure structure. Near the top Gd₂₄Co₇₆ layer, local exchange springs with out-of-plane magnetization reversal, quasi-domains with ripple-like patterns and magnetic vortices and antivortices across the thickness are observed. The detailed analysis of the magnetic tomogram shows that the effective strength of the exchange spring at the NdCo/GdCo interface can be finely tuned by Gd_xCo_1-x composition and anisotropy (determined by sample fabrication) and in-plane stripe orientation (adjustable), demonstrating the suitability of 3D magnetic visualization techniques in magnetic engineering research.

Full control of magnetic properties in exchange coupled multilayers requires a good understanding of 3D magnetic configuration. Here, soft x-ray magnetic tomography is performed to obtain, solely from experimental data, the vector magnetic configuration of a ferrimagnetic trilayer with engineered competing exchange/magnetostatic interactions at different depths.