Random spin signal in magnetic resonance force microscopy

We study a random magnetic resonance force microscopy (MRFM) signal caused by the thermal vibrations of high frequency cantilever modes in the oscillating cantilever-driven adiabatic reversals (OSCAR) technique. We show that the regular MRFM signal with a characteristic decay time, τm, is followed by a non-dissipative random signal with a characteristic time τr. We present the estimates for the values of τm and τr. We argue that this random MRFM signal can be used for spin detection. It has a 'signature' of a sharp peak in its Fourier spectrum