AbstractThe interplay of superconductivity and magnetism is a subject of ongoing interest, stimulated most recently by the discovery of Fe-based superconductivity and the recognition that spin-fluctuations near a magnetic quantum critical point may provide an explanation for the superconductivity and the order parameter. Here we investigate magnetism in the Na filled Fe-based skutterudites using first principles calculations. NaFe₄Sb₁₂ is a known ferromagnet near a quantum critical point. We find a ferromagnetic metallic state for this compound driven by a Stoner type instability, consistent with prior work. In accord with prior work, the magnetization is overestimated, as expected for a material near an itinerant ferromagnetic quantum critical point. NaFe₄P₁₂ also shows a ferromagnetic instability at the density functional level, but this instability is much weaker than that of NaFe₄Sb₁₂, possibly placing it on the paramagnetic side of the quantum critical point. NaFe₄As₁₂ shows intermediate behavior. We also present results for skutterudite FeSb₃, which is a metastable phase that has been reported in thin film form.