Probing magnetic ordering in air stable iron-rich van der Waals minerals

Muhammad Zubair Khan; Oleg E. Peil; Apoorva Sharma; Oleksandr Selyshchev; Sergio Valencia; Florian Kronast; Maik Zimmermann; Muhammad Awais Aslam; Johann G. Raith; Christian Teichert; Dietrich R. T. Zahn; Georgeta Salvan; Aleksandar Matković; Chair of Physics; Department Physics; Mechanics; Electrical engineering; Montanuniversität Leoben; 8700; Leoben; Austria.; Materials Center Leoben Forschung GmbH; Semiconductor Physics; Chemnitz University of Technology; D-09107; Chemnitz; Germany.; Department of Spin; Topology in Quantum Materials; Helmholtz-Zentrum Berlin; Albert-Einstein-Str. 15; D-12489; Berlin; Chair of Resource Mineralogy; Centre for Materials; Architecture; Integration of Nanomembranes; 09126; Germany

arXiv · 2304.06533

Probing magnetic ordering in air stable iron-rich van der Waals minerals

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Abstract

In the rapidly expanding field of two-dimensional materials, magnetic monolayers show great promise for the future applications in nanoelectronics, data storage, and sensing. The research in intrinsically magnetic two-dimensional materials mainly focuses on synthetic iodide and telluride based compounds, which inherently suffer from the lack of ambient stability. So far, naturally occurring layered magnetic materials have been vastly overlooked. These minerals offer a unique opportunity to explore air-stable complex layered systems with high concentration of local moment bearing ions. We demonstrate magnetic ordering in iron-rich two-dimensional phyllosilicates, focusing on mineral species of minnesotaite, annite, and biotite. These are naturally occurring van der Waals magnetic materials which integrate local moment baring ions of iron via magnesium/aluminium substitution in their octahedral sites. Due to self-inherent capping by silicate/aluminate tetrahedral groups, ultra-thin layers are air-stable. Chemical characterization, quantitative elemental analysis, and iron oxidation states were determined via Raman spectroscopy, wavelength disperse X-ray spectroscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy. Superconducting quantum interference device magnetometry measurements were performed to examine the magnetic ordering. These layered materials exhibit paramagnetic or superparamagnetic characteristics at room temperature. At low temperature ferrimagnetic or antiferromagnetic ordering occurs, with the critical ordering temperature of 38.7 K for minnesotaite, 36.1 K for annite, and 4.9 K for biotite. In-field magnetic force microscopy on iron bearing phyllosilicates confirmed the paramagnetic response at room temperature, present down to monolayers.

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Muhammad Zubair Khan, Oleg E. Peil, Apoorva Sharma, Oleksandr Selyshchev, Sergio Valencia, Florian Kronast, Maik Zimmermann, Muhammad Awais Aslam, Johann G. Raith, Christian Teichert, Dietrich R. T. Zahn, Georgeta Salvan, Aleksandar Matković, Chair of Physics, Department Physics, Mechanics, Electrical engineering, Montanuniversität Leoben, 8700, Leoben, Austria., Materials Center Leoben Forschung GmbH, Semiconductor Physics, Chemnitz University of Technology, D-09107, Chemnitz, Germany., Department of Spin, Topology in Quantum Materials, Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, D-12489, Berlin, Chair of Resource Mineralogy, Centre for Materials, Architecture, Integration of Nanomembranes, 09126, Germany. 2023-04-13. Probing magnetic ordering in air stable iron-rich van der Waals minerals. https://arxiv.org/abs/2304.06533

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