In this thesis we present a project concerned with combining a flux concentrator coil with a persistent current switch. We show that this coil with core of specific design is capable of creating...Show moreIn this thesis we present a project concerned with combining a flux concentrator coil with a persistent current switch. We show that this coil with core of specific design is capable of creating fields of at least several tens of milliTeslas in a small region (100µm cubic) at low current. We also provide our acquiring of the relative magnetic permeability of metallic glass 2605SA1 and conclude that this material is sufficiently magnetizable at milliKelvin temperatures to be used as transformer cores in dilution refrigerators. Furthermore, we show how the persistent current switch we built is capable of holding a superconducting current loop with a lifetime of at least several minutes.Show less
An indispensable ingredient for nanoscale imaging within the field of Magnetic Resonance Force Microscopy (MRFM) is a radiofrequency (RF) source. Conventional RF-sources constitute a significant...Show moreAn indispensable ingredient for nanoscale imaging within the field of Magnetic Resonance Force Microscopy (MRFM) is a radiofrequency (RF) source. Conventional RF-sources constitute a significant impediment for MRFM experiments at extreme low temperatures and consequently form a major obstacle towards the single-spin measurement. In this thesis we have introduced a non-trivial method where an intrinsic property of an MRFM force sensor is exploited for the generation of an ultra-low dissipative RF-field. Using MRFM as a probe for local nuclear magnetic resonance (NMR) experiments on copper nuclei at millikelvin temperatures, we have demonstrated that the correct implementation of this feature resulted in an amplification of the NMR signal by more than a factor 2. Based on these findings, we propose an adjusted design of the force sensor that could contribute towards a significantly improved imaging sensitivity as established in MRFM experiments to date.Show less
We have investigated the technical feasibility of a novel concept within the scientific field of magnetic resonance force microscopy (MRFM), in which a cantilever is used as a force sensor on the...Show moreWe have investigated the technical feasibility of a novel concept within the scientific field of magnetic resonance force microscopy (MRFM), in which a cantilever is used as a force sensor on the one hand and a radio frequency (rf) source on the other. By driving a magnet-tipped cantilever at a higher resonance mode, the rotational motion of the magnetic tip generates an oscillating magnetic field. In this way the cantilever can serve as an ultra-low dissipative rf source with an rf frequency corresponding to the specific higher mechanical resonance mode of the cantilever. In this work we have tested this idea for an attonewton-sensitivity silicon cantilever with a high magnetic gradient cobalt nanomagnet attached at the cantilever's free end. Using frequency-shift cantilever magnetometry, we found that the nanomagnet's remanent magnetisation is 0.83 tesla. When the nanomagnet is close enough to a spin-containing sample, we have calculated that the nanomagnet's magnetisation - even at zero applied magnetic field - can mechanically generate an rf field of the order millitesla. This implies that the protocol for adiabatic rapid passage can be conducted without the use of an rf wire as a radio frequency source, which eliminates a major dissipation channel that constitutes an obstacle to date for lower working temperatures in high resolution 3D-imaging experiments with MRFM.Show less
