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.

MnBi2Te4, Mn(Bi,Sb)2Te4, and MnBi2Te4(Bi2Te3)m (m ≥ 1) are assigned to magnetic topological insulators. Successful application of these materials in nanoelectronic devices calls for comprehensive investigation of their electronic structure and magnetic properties in dependence of the Bi/Sb atomic ratio and the number m of Bi2Te3 blocks. The magnetic properties of the surface of MnBi2Te4, MnBi4Te7, and Mn(Bi _1-x Sbx)2Te4 compounds (x = 0.43 and 0.32) have been studied using the magneto-optical Kerr effect. It is shown that the temperatures of magnetic transitions on the surface and in the bulk of MnBi4Te7 and Mn(Bi, Sb)2Te4 differ significantly.

Материалы MnBi2Te4, Mn(Bi,Sb)2Te4 и MnBi2Te4(Bi2Te3)m (где m ≥ 1) относятся к классу магнитных топологических изоляторов. Для успешного применения данных материалов в устройствах наноэлектроники необходимо всестороннее изучение их электронной структуры и магнитных свойств в зависимости от соотношения атомов Bi/Sb и количества (m) блоков Bi2Te3. Изучались магнитные свойства поверхности соединений MnBi2Te4, MnBi4Te7 и Mn(Bi1–xSbx)2Te4 (где x = 0.43, 0.32) при помощи магнитооптического эффекта Керра. Показано, что температуры магнитных переходов на поверхности и в объеме MnBi4Te7 и Mn(Bi,Sb)2Te4 существенно различаются.

The features of the magnetic state of an array of parallel oriented permalloy ribbons are discussed. The arrays are made by explosive lithography. The ribbons have a thickness of 180 nm, a width of 2.8 µm, and a length of about 4 mm. The distance between ribbons in different samples varies in the range from 300 nm to 4 μm. It is found that the ribbons in the regions far from the end faces are in a single-domain state with small-angle ripples, the magnetization distribution of which correlates with inhomogeneities of the ribbon side surfaces. Moreover, there is a distinct relationship in the spatial distribution of the ripples between adjacent ribbons with a relatively small distance between them. This makes it possible to evaluate the role of the magnetostatic coupling of magnetic subsystems of array elements and to estimate the characteristic value of the random stray field that pins the magnetization.

The optical and magneto-optical properties of the DyxCo1-x/Bi/NiFe three-layer systems are presented. The magneto-optical Kerr effect to study the temperature dependence of the magnetization and spectroscopic ellipsometry to obtain optical constants were used. It is shown that the thickness of the bismuth interlayer affects the exchange interaction between the NiFe and DyCo layers, which is manifested in a change of the magnetisation compensation temperature.