  Kagome lattice magnets are an interesting class of materials as they can host
topological properties in their magnetic and electronic structures. YMn6Sn6 is
one such compound in which a series of competing magnetic phases is stabilized
by an applied magnetic field, and both an enigmatic topological Hall effect and
a Dirac crossing close to the Fermi energy have been realized. This material
also shows a magnetization-induced Lifshitz transition and evidence of a unique
charge spin coupling in one of the magnetic phases, namely the fan-like phase.
Tuning the magnetism, and thus the interplay with the electronic states, opens
new avenues for precise control of these novel properties. Here, we demonstrate
the extreme sensitivity of the magnetic phases in YMn6Sn4Ge2 through the
investigation of structural, magnetic, and transport properties. The high
sensitivity to small doping provides great potential for engineering the
magnetic phases and associated electronic properties in this family of
rare-earth kagome magnets.
