Double-spiral magnetic structure of the Fe/Cr multilayer revealed by nuclear resonance scattering

We have studied the magnetization depth profiles in a [57Fe(dFe)/Cr(dCr)]x30 multilayer with ultrathin Fe layers and nominal thickness of the chromium spacers dCr 2.0 nm using nuclear resonance scattering of synchrotron radiation. The presence of a broad pure-magnetic half-order (1/2) Bragg reflection has been detected at zero external field. The joint fit of the reflectivity curves and Mossbauer spectra of reflectivity measured near the critical angle and at the "magnetic" peak reveals that the magnetic structure of the multilayer is formed by two spirals, one in the odd and another one in the even iron layers, with the opposite signs of rotation. The double-spiral structure starts from the surface with the almost antiferromagnetic alignment of the adjacent Fe layers. The rotation of the two spirals leads to nearly ferromagnetic alignment of the two magnetic subsystems at some depth, where the sudden turn of the magnetic vectors by ~180 deg (spin-flop) appears, and both spirals start to rotate in opposite directions. The observation of this unusual double-spiral magnetic structure suggests that the unique properties of giant magneto-resistance devices can be further tailored using ultrathin magnetic layers.Comment: 9 pages, 3 figure

Electromagnetic waves in a rectangular waveguide with metallic nanostructure

The propagation of microwave electromagnetic waves in a rectangular waveguide with a multilayer metallic nanostructure is considered. The nanostructure is parallel to the waveguide axis with the layer planes perpendicular to the waveguide narrow wall. Using perturbation theory, adjustments for the complex propagation constant are derived. The frequency dependence of reflection and transmission coefficients is determined. Experiments on the measurement of the standing-wave ratio and transmission coefficient of millimeter waves propagating in a waveguide with a (Fe/Cr) n multilayer nanostructure are carried out

Electromagnetic wave reflection from Fe/Cr nanostructures

The reflection of electromagnetic waves in the millimeter wave band from Fe/Cr nanostructures has been studied. It is established that the giant magnetoresistance (GMR) in the nanostructure leads to an increase in the reflection and a decrease in the transmission of microwaves, while the magnetic resonance leads to a decrease in both the reflection and transmission coefficients

Giant magnetoresistive effect and magnetic resonance in the reflection of electromagnetic waves from Fe-Cr nanostructures

The influence of the giant magnetoresistive effect and magnetic resonance on the reflection of an electromagnetic wave from multilayer Fe-Cr nanostructures is studied. The experiments are performed at a frequency of 27-38 GHz in magnetic fields up to 13 kOe. The magnetoresistive effect is shown to increase the reflected-wave amplitude, and the magnetic resonance manifests itself in the form of a sharp decrease in this amplitude. The experimental results are analyzed theoretically. © Pleiades Publishing, Ltd., 2009.Российский Фонд Фундаментальных Исследований (РФФИ): 07 02 01289Russian Academy of SciencesThis work was performed according the SPIN project (registration no. 01.2.00613391) and was sup ported in part by the Russian Foundation for Basic Research (project no. 07 02 01289) and the Presid ium of the Russian Academy of Sciences (programs “Spintronics” and “Foundations of Fundamental Studies of Nanotechnologies and Nanomaterials”)

Magnetic field driven waveguide with metallic nanostructure

The changes in the propagation constant of the H10 mode of a rectangular waveguide with a metallic nanostructure, occurring under an external magnetic field have been investigated. Expressions for complex reflection and transmission coefficients have been derived. The dependence of the reflection coefficient on the intensity of the external magnetic field is analyzed. It is shown that the experimental values of the propagation constant or the reflection and transmission coefficients can be used to estimate the value of the microwave magnetoresistance of nanostructures. Experiments on the measurement of the reflection and transmission coefficients in a waveguide with an (Fe/Cr)n nanostructure have been performed in millimeter and centimeter wave bands. © 2006 EuMA

Rectangular waveguide with metallic nanostructure driven by magnetic field

The changes in the propagation constant of the TE 10 mode of a rectangular waveguide with a metallic nanostructure, occurring under an external magnetic field have been investigated. Expressions for complex reflection and transmission coefficients have been derived. The dependence of the reflection coefficient upon the intensity of the external magnetic field is analyzed. It is shown that the experimental values of the propagation constant or the reflection and transmission coefficients can be used to estimate the value of the microwave magnetoresistance of nanostructures. Experiments on the measurement of the reflection and transmission coefficients in a waveguide with an (Fe/Cr)n nanostructure have been performed in millimeter and centimeter wave bands. © Springer Science+Business Media, LLC 2007.Российский Фонд Фундаментальных Исследований (РФФИ)Russian Academy of SciencesThe research was partly supported by RFBR and the Quantum Macrophysics Program of RAS

High-frequency properties of Fe/Cr superlattices with thin Cr layers in the millimeter-wavelength range

Microwave properties of Fe/Cr multilayer nanostructures with thin chromium layers (with thickness t Cr < 1 nm) are analyzed. Experiments are performed by the method of penetration of microwaves in the frequency range from 26 to 38 GHz. The dependence of the transmission coefficient for microwaves on the constant magnetic field strength exhibits the microwave magnetoresistive effect and magnetic resonance. The resonance spectrum is reconstructed from measurements at various frequencies. The results of microwave measurements are analyzed together with the results of magnetic and magnetoresistive measurements. © 2013 Pleiades Publishing, Ltd.Russian Foundation for Basic Research, РФФИ: 10 02 00590

Transmission of Microwaves through Magnetic Metallic Nanostructures

Abstract: The penetration of decimeter, centimeter, and millimeter electromagnetic waves through magnetic metallic nanostructures is considered in this work. Detailed information on the microwave giant magnetoresistive effect is presented. The manifestations of ferromagnetic and spin-wave resonances upon the transmission of microwaves through nanostructures are considered. © 2020, Pleiades Publishing, Ltd.Ministry of Education and Science of the Russian Federation, Minobrnauka: AAAA-A18-118020290104-2, AAAA-A19-119012990095-0 Russian Science Foundation, RSF: 17-12-01002

GMR effect and magnetic resonance of metallic nanostructures on microwaves

Microwave properties of magnetic metallic nanostructures with giant magnetoresistive effect are studied. Two main physical reasons cause microwave variations, namely the microwave analog of giant magnetoresistive effect and ferromagnetic resonance. A comparison is outlined with the DC magnetoresistive effect. Methods of microwave magnetoresistive effect measurement are presented. The experiments in the "current perpendicular-to-plane" geometry are specially considered, and the experiments carried out in the millimeter waveband are presented. The peculiarities of the joint observation of ferromagnetic resonance and microwave magnetoresistive effect are specified. Application of the metallic magnetic nanostructures in microwave electronics is discussed

Microwave penetration and magnetic resonance in cluster-layered Fe/Cr nanostructures

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