Berlin 2024 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 5: Thin oxides and oxide layers (joint session DS/KFM)
KFM 5.1: Vortrag
Montag, 18. März 2024, 09:30–09:45, A 053
Non-collinear spin texture in thin rare-earth ion doped nickel ferrite films — •Anupam K. Singh1, Katayoon Mohseni1, Malleshwara R. Tangi1, Verena Ney2, Andreas Ney2, Arthur Ernst2, Yicheng Guan1, Manuel Valvidares3, P. Gargiani3, Ilya Kostanvoskiy1, Holger L. Meyerheim1, and Stuart S. P. Parkin1 — 1Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany — 2Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz, Austria — 3ALBA Synchrotron, E-08290 Cerdanyola del Valle`s, Barcelona, Spain
Ferrites are abundantly used as magnetic materials, but thus far, the detailed magnetic structure in ultra-thin films has escaped clear-cut characterization. The recent observation of rare-earth-induced DMI in low-dissipation insulating oxides calls for a deeper insight into their spin texture [1]. We have studied the atomic and magnetic structure of 5 to 40 nm thick Dy-doped (5%) Zn/Al-substituted nickel ferrite (Ni0.65Zn0.35Al0.8Fe1.2O4) films prepared by magnetron sputtering. Characterization by RBS, XRD, EXAFS and XMCD experiments at the Fe-K, L2,3 and the Dy-L2,3, M4,5 edges establish the formation of a tetragonally distorted spinel structure where Dy3+ ions occupy octahedral sites with a redistribution of the Fe2+ and Fe3+ cations. Temperature-dependent SQUID, XMCD and MOKE experiments indicate a spin-reorientation transition from in-plane easy axis below 200 K, thereby showing a non-monotonic behavior of the M(T) curve which is interpreted as due to the formation of a non-collinear spin structure. [1] L. Caretta, et al., Nat. Comm. 11, 1090 (2020).
Keywords: Non-collinear; Spinel; Nickel ferrite; x-ray absorption spectroscopy; Magneto-optic Kerr effect