How does Cr doping Mn(3-x)CrxSn influence the magnetic interactions?

Mn3Sn and Mn$_3$Ge display a large Anomalous Hall Effect (AHE) at room temperature, which can easily be controlled with a weak external magnetic field. It is therefore an excellent candidate material for spintronic applications The large AHE is closely linked to the magnetic structure, where the Mn spins in the triangular ab plane form a 120 degree structure which breaks inversion symmetry. However, Mn3Sn enters a helical phase upon cooling below 290 K, and the AHE vanishes. We are investigating how to tune the AHE using chemical substitution. Very recent results indicate that the helical phase can be suppressed by small amounts of Cr. We further find that the low energy excitations show signatures of proximity to the helical phase. The helical phase in the parent compound is stabilized by the interplay of up to 8th nearest exchange interactions, as well as anisotropy. We here want to complete our inelastic study of Mn(3-x)CrxSn. We will do this by measuring the spin waves in Mn(3-x)CrxSn, to determine how these parameters change to suppress the helical phase and preserve the AHE.