In two-dimensional (2D) ferromagnets, anisotropy is important for the magnetic ordering as dictated by the Mermin-Wagner theorem. The not too long ago found van der Waals ferromagnets are largely thought-about to have uniaxial anisotropy. Alternatively, honeycomb lattice is proof against magnetic frustration even with antiferromagnetic alternate coupling resulting from its bi-partite unit cell.
Nonetheless, usually ignored interlayer coupling could considerably alter the vital conduct and even the floor state. It’s particularly so when the interlayer alternate anisotropy has related magnitude and reverse signal from the intralayer anisotropy. When such competing anisotropies are current, the section transition turns into nontrivial. Probing the section transition in 2D ferromagnets below competing anisotropies requires extremely delicate and direct magnetic microscopies and is up to now missing.
Shiyuan Wang and colleagues from Fudan College and collaborators from Renmin College employed the excessive flux sensitivity of scanning superconducting quantum interference gadget microscopy (sSQUID) on investigating the vital conduct of a ferromagnetic honeycomb lattice from the majority to 2D restrict. They probed the spin correlations of ABC-stacked CrBr3 below zero magnetic subject. Within the thick samples, they noticed a spike and a plateau area as a operate of temperature in susceptibility, which was as a result of competitors between intra- and inter-layer anisotropies.
The spike and the plateau areas broadened and merged with decreasing thickness. This reached the restrict within the bilayer, the place the fluctuation regime is as extensive because the transition temperature. This conduct was distinct from each the monolayer and the majority. The evolution of the vital conduct from the majority to 2D confirmed that the competitors between the anisotropies was magnified within the diminished dimension.
Their remark suggests a annoyed ferromagnetic section transition in AB-stacked bilayer CrBr3. It demonstrates susceptometry based mostly on sSQUID holds the potential for finding out spin frustration in 2D supplies.
The examine is revealed within the journal Science Bulletin.
Extra info:
Shiyuan Wang et al, Pissed off ferromagnetic transition in AB-stacked honeycomb bilayer, Science Bulletin (2022). DOI: 10.1016/j.scib.2022.12.009
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Pissed off ferromagnetic transition in AB-stacked honeycomb bilayer (2023, February 16)
retrieved 18 February 2023
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