Magnetic structure determination of novel intercalated van der Waals magnets

The discovery of van der Waals magnets has led to unprecedented opportunities for investigation of magnetism in the 2D limit. Currently, various vdW magnets have been realized, including (anti-)ferromagnetic metals, semiconductors and insulators. Despite the exciting progress, a key challenge is that their weak interlayer coupling generally results in low magnetic transition temperatures, well below room temperature. Research efforts have therefore focused on designing novel vdW magnets with increased transition temperatures. One approach that we have developed is the introduction of guest molecules in the van der Waals gap for tuning interlayer distances and therefore leading to profound modification of the electronic and magnetic structure.
Specifically, we have for the first time intercalated the semiconducting antiferromagnetic vdW magnet, CrSBr – which has risen to the forefront of condensed matter research – with different organic cations: tetramethylammonium (TMA) and tetrapentylammonium (TPA). Intercalation of CrSBr has strongly influenced its magnetic properties, converting it from an antiferromagnet to ferromagnet, and increasing its magnetic transition temperature from 130 K to 200 K.
We aim to elucidate the nature of the magnetic phase of newly intercalated TMA- and TPA-CrSBr and to clarify the nature of interlayer molecule ordering for directly correlating changes in magnetic behaviour with molecular crystal size and symmetry.