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Theme 3 colloquium: 'Magnetic 2D materials: From 2D magnets to molecular/2D magnetic heterostructures' (Lecture)

Tuesday 20 September 2022Add to my calendar
from 16:00
Prof. Dr. Eugenio Coronado (Institute for Molecular Science (ICMol) of the Universidad de Valencia, Spain)
Two-dimensional (2D) magnetic materials offer unprecedented opportunities for fundamental physics and applied research in spintronics and magnonics. The chemical instability exhibited by  most of these materials has strongly limited the research in this area. Here I will show some recent advances in the area of 2D magnetic materials paying particular  attention to the role played by magnetic molecular systems.
• The CrSBr metamagnetic semiconductor. This relatively air-stable inorganic material is formed  by antiferromagnetically-coupled ferromagnetic layers (T c ~150 K) that can be exfoliated down  to the single-layer. Here, we will unveil open questions regarding the rich 2D physics exhibited  by these low-dimensional materials by inspecting the magneto-transport properties of vertical
heterostructures in the 2D limit. Our results demonstrate the marked low-dimensional character  of the ferromagnetic monolayer, with short-range correlations above T c and an Ising-type in- plane anisotropy, being the spins spontaneously aligned along the easy-axis b below Tc . In the  multi-layer case, a spin-valve behavior is observed [1].
• Molecular 2D magnets. I will focus on the design of molecular 2D antiferromagnets that, in  contrast to what happens with the inorganic 2D magnets, are chemically stable in open air,  keeping their magnetic properties preserved upon functionalizing their surface with different  organic molecules [2].
• Smart molecular/2D heterostructures. I propose to create hybrid heterostructures by  interfacing stimuli-responsive molecular systems with graphene and semiconducting transition  metal dichalcogenides (MoS2 and WSe2 ). The aim is that of tuning the properties of the “all  surface” 2D material via an active control of the hybrid interface. This concept will provide an  entire new class of smart molecular/2D heterostructures, which may be at the origin of a novel
generation of hybrid materials and devices of direct application in highly topical fields like  electronics, spintronics and straintronics. [3-5].

[1] Boix-Constant, C. et al., Probing the spin dimensionality in single-layer CrSBr van der Waals  heterostructures by magneto-transport measurements Adv. Mater. 2022, DOI: 10.1002/adma.202204940
[2] J. Lopez-Cabrelles, J. et al. Chemical Design and Magnetic Ordering in Thin Layers of 2D  Metal-Organic Frameworks (MOFs). J. Am. Chem. Soc. 2021, 143, 18502-18510. DOI:  10.1021/jacs.1c07802
[3] Coronado, E. Molecular magnetism: from chemical design to spin control in molecules, materials and devices. Nature Rev. Mater. 2020, 5, 87-104. DOI: 10.1038/s41578-019-0146-8
[4] Torres-Cavanillas, R. et al. Spin-crossover nanoparticles anchored on MoS 2 layers for heterostructures with tunable strain driven by thermal or light-induced spin switching. Nature Chem. 2021, 13, 1101-1109 . DOI: 10.1038/s41557-021-00795-y
[5] Boix-Constant, C. et al. Strain Switching in van der Waals Heterostructures Triggered by a Spin-Crossover Metal–Organic Framework. Adv. Mater. 2022, 34, 2110027. DOI:10.1002/adma.202110027
Andrey Bagrov and Nadine Hauptmann