In this thesis, we describe the latest advances in SQUID-detected Magnetic Resonance Force Microscopy (MRFM). We have developed a new MRFM setup, which we describe in great detail, in particular... Show moreIn this thesis, we describe the latest advances in SQUID-detected Magnetic Resonance Force Microscopy (MRFM). We have developed a new MRFM setup, which we describe in great detail, in particular our efforts to remove vibrational noise from our dry dilution refrigerator, whilst maintaining the lowest possible operating temperatures, and our solution to reduce the crosstalk between the B1 field and SQUID (Superconducting QUantum Interference Device) detection. We have used the setup to further investigate the MRFM signals of copper nuclei, with a specific focus on the usage of higher modes of the cantilever as source for the B1 field, resulting in an MRFM frequency shift signal from the Boltzmann polarization of spins in a voxel as small as (40 nm)3. Furthermore, we have investigated the spin system in diamond, where we found evidence of the suppression of spin-diffusion in the layer of surface spins due to our high magnetic field gradients. Show less
In the early nineties, Sidles (1991) came with a solution to combine the force microscopy techniques sensitive to atoms with that of magnetic resonance techniques: Magnetic Resonance Force... Show moreIn the early nineties, Sidles (1991) came with a solution to combine the force microscopy techniques sensitive to atoms with that of magnetic resonance techniques: Magnetic Resonance Force Microscopy (MRFM) was born. The technique was promising, big steps were taken, and the holy grail of atomic resolution imaging of biological tissues seemed within an arm’s reach. Unfortunately, the last steps are the most difficult. The technique is experimentally challenging and so far, the images of biological structures are no better than those obtained by other conventional techniques. In order to be an attractive technique, MRFM needs to be scientifically relevant while the technique is further improved towards the holy grail of imaging biological structures on the nanometer scale. In this thesis, we show how MRFM can usefully contribute to the field of condensed-matter. Show less
Nuclear magnetic resonance force microscopy (MRFM) is a technique which combines magnetic resonance imaging (MRI) with scanning probe microscopy (SPM). The final goal is to develop this technique... Show moreNuclear magnetic resonance force microscopy (MRFM) is a technique which combines magnetic resonance imaging (MRI) with scanning probe microscopy (SPM). The final goal is to develop this technique to such a level that the atomic structure of a virus or protein can be revealed by this microscope. This thesis shows nuclear magnetic resonance force measurements on copper in which the interaction of the magnetic moments of the nuclei of copper with a magnetic cantilever has delivered a detectable signal at a temperature of 50 millikelvin. Furthermore, we show measurements, which support a new theory where at low magnetic field and low temperature, non contact friction between the magnetic cantilever and paramagnetic electron spins is described. These measurements were enabled by technical improvements such as vibration reduction in a cryogen free dilution refrigerator. As a benchmark for the low vibration, we show atomic resolution scanning tunneling microscopy at 15 millikelvin temperature on graphite. We also show a method to create small magnets for MRFM from a thin magnet film. With these small magnets the field gradient and therefore the sensitivity may be significantly enhanced. Show less
