Influence of the DyxCo1-x–Bi Interface on the Magnetic Properties of DyxCo1-x/Bi/Py Three-Layer Structures

Kosyrev, N.N., Patrin, G.S., Shiyan, Y.G., (...), Komarov, V.A., Semenov, S.V.// Journal of Superconductivity and Novel Magnetism//

The interlayer interactions in multilayer systems with a non-magnetic semimetallic interlayer are great of interest. The magnetic and structural properties of the DyxCo1-x/Bi/Py systems (17 < x < 26 at.%) have been studied. The temperature dependences of magnetization in the range 4.2–300 K were measured for the first time. The influence of the bismuth interlayer thickness on the exchange interaction between the DyCo and Py layers was found as well as the critical value of its thickness. The obtained atypical value of the period of exchange bias oscillations was explained by the formation of bismuth compounds with dysprosium–pnictogenides at bismuth thicknesses below the critical value. The interface was investigated by spectral ellipsometry in the range 2–5 eV. The information on the structure of the surface obtained by atomic force microscopy was used to create a multilayer model for fitting experimental ellipsometric data. Analysis of the optical properties showed that pnictogenide Dy3Bi2 is formed at the interface, which affects the general magnetic state of the samples studied.