TY - JOUR

T1 - Probing Magnetic Ordering in Air Stable Iron‐Rich Van der Waals Minerals

AU - Khan, Muhammad Zubair

AU - Peil, Oleg

AU - Sharma, Apoorva

AU - Selyshchev, Oleksandr

AU - Valencia, Sergio

AU - Kronast, Florian

AU - Zimmermann, Maik

AU - Aslam, Muhammad Awais

AU - Raith, Johann

AU - Teichert, Karl Christian

AU - Zahn, Dietrich R. T.

AU - Salvan, Georgeta

AU - Matković, Aleksandar

PY - 2023/7/26

Y1 - 2023/7/26

N2 - Magnetic monolayers show great promise for future applications in nanoelectronics, data storage, and sensing. The research in magnetic two-dimensional (2D) materials focuses on synthetic iodides and tellurides, which suffer from a lack of ambient stability. So far, naturally occurring layered magnetic materials have been overlooked. These minerals offer a unique opportunity to explore complex air-stable layered systems with high concentration of magnetic ions. Magnetic ordering in iron-rich phyllosilicates is demonstrated, focusing on minnesotaite, annite, and biotite. These naturally occurring layered materials integrate local moment baring ions of iron via magnesium/aluminum substitution in their octahedral sites. Self-inherent capping by silicate/aluminate tetrahedral groups enables air stability of ultra-thin layers. 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 magnetic ordering. Paramagnetic or superparamagnetic characteristics at room temperature are observed. Below 40 K ferrimagnetic or antiferromagnetic ordering occurs. In-field magnetic force microscopy on exfoliated flakes confirms that the paramagnetic response at room temperature persists down to monolayers. Further, a correlation between the mixture of the oxidation states of iron and the critical ordering temperature is established, indicating a path to design materials with higher critical temperatures via oxidation state engineering.

AB - Magnetic monolayers show great promise for future applications in nanoelectronics, data storage, and sensing. The research in magnetic two-dimensional (2D) materials focuses on synthetic iodides and tellurides, which suffer from a lack of ambient stability. So far, naturally occurring layered magnetic materials have been overlooked. These minerals offer a unique opportunity to explore complex air-stable layered systems with high concentration of magnetic ions. Magnetic ordering in iron-rich phyllosilicates is demonstrated, focusing on minnesotaite, annite, and biotite. These naturally occurring layered materials integrate local moment baring ions of iron via magnesium/aluminum substitution in their octahedral sites. Self-inherent capping by silicate/aluminate tetrahedral groups enables air stability of ultra-thin layers. 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 magnetic ordering. Paramagnetic or superparamagnetic characteristics at room temperature are observed. Below 40 K ferrimagnetic or antiferromagnetic ordering occurs. In-field magnetic force microscopy on exfoliated flakes confirms that the paramagnetic response at room temperature persists down to monolayers. Further, a correlation between the mixture of the oxidation states of iron and the critical ordering temperature is established, indicating a path to design materials with higher critical temperatures via oxidation state engineering.

U2 - 10.1002/apxr.202300070

DO - 10.1002/apxr.202300070

M3 - Article

VL - 2.2023

JO - Advanced physics research

JF - Advanced physics research

IS - 12

M1 - 2300070

ER -