Accurate measurement of atomic magnetic moments by minimizing the tip magnetic field in STM-based electron paramagnetic resonance

Electron paramagnetic resonance (EPR) performed with a scanning tunneling microscope (STM) allows for probing the spin excitation of single atomic species MHz energy resolution. One basic applications conventional EPR is precise determination magnetic moments. However, in an STM, local fields spin-polarized tip can introduce systematic errors measurement moments by EPR. We propose to solve this issue finding tip-sample distances at which shift caused field minimized. To end, we measure dependence on distance different radiofrequencies and identify specific true moment found. Additionally, show that tip's influence be averaged out using magnetically bistable tips, provides complementary method accurately surface atoms STM.