Generating Ferromagnetic Kagome Metal by Magnetic\nPhase Boundary Mapping in the YFe<sub>6</sub>Ge<sub>6</sub>–YCo<sub>6</sub>Ge<sub>6</sub> System

We demonstrate the possibility to\ngenerate itinerant ferromagnetism\non a kagomé lattice by varying the structural parameters and\nvalence electron concentration between antiferromagnetic YFe<sub>6</sub>Ge<sub>6</sub> and paramagnetic YCo<sub>6</sub>Ge<sub>6</sub>. The\nsubstitution of Co for Fe in orthorhombic YFe<sub>6</sub>Ge<sub>6</sub> leads to the gradual suppression of the antiferromagnetic ordering\ntemperature in YFe<sub>6–<i>x</i></sub>Co<sub><i>x</i></sub>Ge<sub>6</sub>. At a higher Co content, <i>x</i> ≥ 4, ferromagnetic-like behavior is observed along with the\nchange in the symmetry to the hexagonal YCo<sub>6</sub>Ge<sub>6</sub>-type structure. Finally, the magnetic ordering is completely suppressed\nin YCo<sub>6</sub>Ge<sub>6</sub>. Density-functional theory calculations\nreveal that the suppression of magnetic ordering is caused by the\nfilling of 3d states in the band structure of these materials. This\nwork suggests the pathway to discover new ferromagnetic kagomé\nmetals by judicious variation of the electronic band structure via\nthe control of valence electron concentration.