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

STUDIES OF STRUCTURAL CHANGES IN HYDROGENATED Fe/Gd SUPERLATTICES BY X-RAY DIFFRACTION AND REFLECTOMETRY

The article is devoted to the study of the effect of hydrogenation on the structural properties of Fe/Gd superlattices. It was found that as a result of the penetration of hydrogen into the gadolinium layers, the period of the Fe/Gd superlattice increases and additional phases GdH2 and GdH3 appear.Работа выполнена в рамках государственного задания МИНОБРНАУКИ России (тема «Спин» № 122021000036-3)

Influence of Dimensional Effects on the Curie Temperature of Dy and Ho Thin Films

Abstract: The role of size effects in the formation of the magnetic structure of Dy and Ho thin films in absence of epitaxial strain is studied in this work. It was found that, for Dy in the temperature range between the Néel temperature and the Curie temperature of bulk Dy and, for Ho, in the temperature range between the Néel temperature and the temperature of phase transition into the conic phase, the temperature dependences of the period of magnetic helicoid in the bulk and film metals are similar. The character of the transition into the ferromagnetic phase in the Dy films changes at lower temperatures, and the transition into the commensurable conic phase in the Ho films is suppressed. This is explained exclusively by the influence of dimensional effects. © 2021, Pleiades Publishing, Ltd.Synthesis of samples and magnetometric measurements were performed at the Center of the Collaborative Access, Institute of Metal Physics, Ural Branch, Russian Academy of Sciences. Experimental data obtained with the REMUR reflectometer were transformed from the instrumental coordinate system into the reciprocal space coordinate system using Överlåtaren software []. This study was supported by the Russian Foundation for Basic Research, project no. 19-32-90007

INFLUENCE OF THE CRYSTAL STRUCTURE ON THE MAGNETIC PROPERTIES OF DY

Four thin Dy films were grown on different surfaces and their structure investigated by means of XRD. The following analysis of magnetisation dependencies allowed to determine interconnection between structural and magnetic properties of the sample.Исследование выполнено при поддержке РФФИ в рамках научного проекта № 19-32-50015. Синтез образцов, рентгеноструктурные и магнитометрические измерения были выполнены в центре коллективного пользования ИФМ УрО РАН

Erratum to: Influence of Dimensional Effects on the Curie Temperature of by and Ho Thin Films (Physics of Metals and Metallography, (2021), 122, 5, (465-471), 10.1134/S0031918X21050033)

An Erratum to this paper has been published: https://doi.org/10.1134/S0031918X21880013. © 2021, Pleiades Publishing, Ltd

Nuclear resonance reflectivity from a [57Fe/Cr]30 multilayer with the Synchrotron Mössbauer Source

Mössbauer reflectivity spectra and nuclear resonance reflectivity (NRR) curves have been measured using the Synchrotron Mössbauer Source (SMS) for a [57Fe/Cr]30 periodic multilayer, characterized by the antiferromagnetic interlayer coupling between adjacent 57Fe layers. Specific features of the Mössbauer reflectivity spectra measured with π-polarized radiation of the SMS near the critical angle and at the 'magnetic' maximum on the NRR curve are analyzed. The variation of the ratio of lines in the Mössbauer reflectivity spectra and the change of the intensity of the 'magnetic' maximum under an applied external field has been used to reveal the transformation of the magnetic alignment in the investigated multilayer.Mössbauer reflectivity experiments performed using the Synchrotron Mössbauer Source at the ESRF demonstrate the high efficiency of such investigations for the analysis and understanding of multilayer structures and magnetization profiles. © International Union of Crystallography, 2018.Russian Foundation for Basic Research, RFBR: 15-02-01674-a, 15-02-01502-a, 16-02-00887-aRussian Academy of Sciences, RASFederal Agency for Scientific Organizations: 1.1.3.5, 01201463330Funding for this research was provided by the Russian Federal Agency for Scientific Organizations on the theme ‘Spin’ No. 01201463330 and by the Project No. 1.1.3.5. of the Program No. 32 of the Presidium of Russian Academy of Sciences, and the research was supported in part by the Russian Foundation for Basic Research (Grants No. 15-02-01674-a, No. 15-02-01502-a and No. 16-02-00887-a)