Efficiency of the turbulent transport of the chemicals and comparison with the one of angular momentum. (a) Turbulent chemical diffusivity and (b) turbulent Schmidt number Sc_T as a function of 𝒩. The black circle shows the unstratified fiducial dynamo run U0. The symbol color of the stratified runs codes the Prandtl number Pr as indicated in the legend in (a). Error bars in (a) show 1 standard deviation intervals around the time averaged turbulent diffusivity values. The dashed line in (a) displays a power law fit of the stratified runs at Pr = 10⁻³, that is . The errors in (b) are obtained by propagating the uncertainties of the turbulent viscosity and of the turbulent diffusivity .