Spectral turnover Γ_s−Γ_h as function of the magnetic field B (left panel) and spin-down (right panel) for all magnetars for which Γ_s and Γ_h are measured. Red circles represent total flux and blue triangles represent pulsed flux. Error bars represent 1σ uncertainties. Linear fits are shown on the left panel, both for pulsed flux (blue line) and total flux (red line), and on the right panel for pulsed flux (blue line). For total flux data in the right panel, the best-fitting quadratic trend is shown. The figure is an updated version of Fig. 9 of Vogel et al. (2014), with the new value of Γ_s−Γ_h for SGR 1900+14 obtained in this work.