MRFM and non-contact friction experiments under UHV conditons

In this contribuiton we present magnetic resonance force microscopy (MRFM ) experiments and non-contact friction force experiments made on $\gamma $-irradiated quarz samples under UHV condtions and low temperatures. Ultrasensitve cantilevers with integrated magnetic tips allow us to detect forces in the order of 10$^{-18 }$N/$\surd $Hz [1]. The measurements showed that the sensitivity did not change significantly in a homogenous magnetic field. In quarz samples long-range, non contact friction forces are observerd. A spin-lifetime of 137 ms was measured by cyclic inversion of the spins. The measurement was achieved with an ultrasensitve PLL using the OSCAR protocol. [1] Gysin et al., Phys. Rev. B \textbf{69}, 045403 (2004)