Muhammad Khan1,Oleg E. Peil2,Nico Klingner3,Gregor Hlawacek3,Sebastian Wintz4,Christian Teichert1,Ulrich Kentsch3,Markus Weigand4,Daniel Knez5,Johann G. Raith6,Andreas Ney7,Aleksandar Matkovic1
Chair of Physics, Department Physics, Mechanics and Electrical Engineering, Montanuniversität Leoben1,Group of Computational Materials Design, Materials Center Leoben Forschung GmBH2,Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden Rossendorf3,Department of Spin and Topology in Quantum Materials, Helmholtz-Zentrum Berlin4,Institute of Electron Microscopy and Nanoanalysis, Graz Centre for Electron Microscopy, Graz University of Technology5,Chair of Resource Mineralogy, Montanuniversität Leoben6,Institute of Semiconductor and Solid State Physics, Johannes Kepler University7
Muhammad Khan1,Oleg E. Peil2,Nico Klingner3,Gregor Hlawacek3,Sebastian Wintz4,Christian Teichert1,Ulrich Kentsch3,Markus Weigand4,Daniel Knez5,Johann G. Raith6,Andreas Ney7,Aleksandar Matkovic1
Chair of Physics, Department Physics, Mechanics and Electrical Engineering, Montanuniversität Leoben1,Group of Computational Materials Design, Materials Center Leoben Forschung GmBH2,Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden Rossendorf3,Department of Spin and Topology in Quantum Materials, Helmholtz-Zentrum Berlin4,Institute of Electron Microscopy and Nanoanalysis, Graz Centre for Electron Microscopy, Graz University of Technology5,Chair of Resource Mineralogy, Montanuniversität Leoben6,Institute of Semiconductor and Solid State Physics, Johannes Kepler University7
The modulation of intrinsic 2D ferromagnetism has gained significant attention and shown a great potential for spintronics. Although many two-dimensional (2D) van der Waals materials have been reported to exhibit intrinsic magnetism, there are still challenges when it comes to ambient stability, which is a crucial barrier for their integration into device applications. We propose to overcome this by exploiting naturally occurring iron-rich phyllosilicates. Phyllosilicates offer a unique opportunity to explore complex air-stable layered systems with high concentration of magnetic ions. These naturally occurring layered materials are inherently magnetic and are wide band gap insulators (i.e. 5-6 eV). These minerals integrate local moment bearing ions of iron via magnesium/aluminium substitution in their octahedral sites. Natural capping by silicate/aluminate tetrahedral groups enables air stability of monolayers.<sup>[1]</sup> Their structure and iron oxidation states are determined via Raman and X-ray spectroscopies. Superconducting quantum interference device magnetometry measurements are performed to examine the long-range magnetic ordering. In-field magnetic force microscopy in the presence of externally applied out-of-plane magnetic field on exfoliated flakes confirms that the paramagnetic response at room temperature persists down to monolayers. We demonstrate correlations between the iron concentration, layer structure, iron oxidation states, and their magnetic response, indicating a path to design materials with higher critical temperatures via oxidation state engineering.<sup>[2]</sup><br/>Furthermore, we also demonstrate a scalable approach to control and tune the concentration of magnetic species via ion implantation into pure phyllosilicates crystals. Controlling the amount of implanted magnetic ions, choosing the dopant species or even alloying in the phyllosilicate matrix will open the pathways to engineer the 2D magnetic insulators with high critical ordering temperature.<br/><br/><u><b>References:</b></u><br/>1 - Matković, Aleksandar, et al. "Iron-rich talc as air-stable platform for magnetic two-dimensional materials." <i>npj 2D Materials and Applications</i> 5.1 (2021): 94.<br/>2- Khan, Muhammad Zubair, et al. ''Probing Magnetic Ordering in Air Stable Iron-Rich Van der Waals Minerals.'' Adv. Phys. Res. (2023).