In-Plane Angular Dependence of Magnetic Anisotropy Energy and Magnetization Processes of Gd Moment Vectors in TM/FeGd/TM Trilayers (TM = Fe, Co) Investigated by X-ray Magnetic Circular Dichroism and Resonant X-ray Magnetic Reflectivity

Element-specific magnetization processes in antiferromagnetically coupled ferro/ferri/ferromagnetic trilayer systems made of Fe/FeGd/Fe and Co/FeGd/Co were investigated by x-ray magnetic circular dichroism (YMCD) spectra and resonant x-ray magnetic reflectivity (RXMR). The magnetic field dependence of the RXMR intensities at the Gd L-3-absorption edge for the Fe/FeGd/Fe trilayer and that of the XMCD and RXMR intensifies at the Gd L-3-, Fe K-, and Co K-absorption edges for the Co/FeGd/Co trilayer were measured. The element-specific magnetization processes of Gd moments with the in-plane applied field were compared between the Fe/FeGd/Fe and Co/FeGd/Co trilayers. The experimental results indicate that the Gd magnetization rotates either clockwise or anticlockwise with equal probability in the Co/FeGd/Co trilayer, whereas it rotates in one direction in the Fe/FeGd/Fe trilayer. The magnetic anisotropics along the in-plane directions were estimated for both trilayers from remanence measurements in various in-plane directions. We discuss the different rotation modes of the Gd magnetization in terms of the distribution of in-plane magnetic easy directions.