Figure 3.

Poor agreement between observed and calculated electron-spin resonance signal vs magnetic field, tip–sample separation, and irradiation frequency for a film with an evaporated gold overlayer. (a) Modulated CERMIT electron-spin resonance signal vs magnetic field $B_0$ at microwave irradiation frequency $f_{\text{MW}}=39.2\text{GHz}$ at various tip–sample separations $h$; the dashed gray line shows the expected field for bulk resonance. (b) Simulation of (a) assuming no magnet damage (${\mu }_0{M}_{\text{s}}=1800\text{mT}$), no sample damage, accounting for incomplete spin saturation due to tip motion for $B_1=24\mu \text{T}$ (see Methods), and accounting for tip motion when calculating the frequency shift (eq 20 in ref 36). The dotted black line represents the tip field at the indicated height $h$. (c) Electron-spin resonance signal vs microwave irradiation frequency at $h=112\text{nm}$.