Doping Induced Itinerant Ferromagnetism in CoAs

The magnetism in $\alpha $-CoAs is dominated by strong spin fluctuations. In this study, we explore the effects of Phosphorus doping in $\alpha $-CoAs. Phosphorus is isovalent with Arsenic, and the resulting doping introduces disorder and chemical pressure. In CoAs$_{\mathrm{1-x}}$P$_{\mathrm{x,}}$ a cross-over from the spin fluctuation-dominated regime to an itinerant ferromagnetic (IFM) state take places around x $=$ 0.04. The IFM state persists up to x $\le $ 0.27. For compositions between x $=$ 0.28 and 0.40, the magnetization data suggests a possible Stoner enhanced state. We acknowledge the support from DOD PECASE.