Figure 2. Spin resonance in conductance across tunnel junction.

(a) NIS junction conductance G as a function of H at V_d.c.=−288 μV and for different f_RF. The black vertical line indicates the critical field of N. H_res and ΔH are obtained for each f_RF by fitting a Lorentzian with a linear background. The fit for f_RF=10.56 GHz is shown (thin red line) and H_res indicated with a red vertical line. (b) H_res and ΔH the resonance linewidth (full width at half maximum) as a function of f_RF (red and blue circles, respectively). A linear fit to H_res(f_RF) data gives a Landé g-factor of 1.95±0.2. The black dots indicate values obtained at different powers or with the second detection scheme. (See Supplementary Note 3 and Supplementary Fig. 3). All dots and circles have been offset by 53 mT to account for a systematic shift in the applied magnetic field during the associated cooldown. The squares indicate values obtained from Device B, in which S is 6-nm thick.