Figure 8.

A spatially dependent sample $T_1$, due to tip magnetization fluctuations, partially explains the electron-spin resonance signal’s dependence on tip–sample separation and magnetic field. Cross-sectional plot of sample $T_1$ calculated for (a) the Figure 6(a) experiment at $h=48\text{nm}$ (cantilever A, assuming $d=5\text{nm}$ and $B_{\text{sat}}=0.95\text{T}$) and (b) the Figure 3(a) experiment at $h=32\text{nm}$ (cantilever B, assuming $d=5\text{nm}$ and $B_{\text{sat}}=1.4\text{T}$). (c, d) Observed (circles) and calculated (lines) electron-spin resonance signal vs magnetic field. The dotted-line calculation assumes no damage layer. The solid-line calculation assumes $h_{\text{damage}}=60\text{nm}$. The simulation in (d) was divided by a factor of 20 to match the experimental signal.