Effect of Cd doping on the structural and magnetic properties of the Kagome flat band compound – Ni₃In

Ni₃In is a rare example of a d-electron system exhibiting the thermodynamic signatures characteristic of heavy fermion and strange metal behaviour. This compound features strong electron correlation effects, driven by the destructive interference of fermion hopping paths, leading to band flattening in the partially filled Ni 3d states. While previous studies have demonstrated that magnetic fields and external pressure can tune this system across a likely quantum critical point, substitutional studies remain unexplored due to the challenges of achieving phase-pure doped samples via conventional solid-state synthesis. In this work, we demonstrate the effective application of ball milling to drastically reduce synthesis time for phase-pure polycrystalline Ni₃In. We further examine the effects of chemical substitution, and we discuss the impact on the electronic structure and magnetic properties.