Magnetic Resonance Force Microscopy Detected Long-Lived Spin Magnetization

Area of Science:

• Physics
• Materials Science
• Chemistry

Background:

• Magnetic resonance force microscopy (MRFM) offers ultra-sensitive spin magnetization detection by combining magnetic resonance imaging and scanning probe microscopy.
• Dynamic nuclear polarization (DNP) can significantly enhance sensitivity, potentially enabling single proton spin detection.

Purpose of the Study:

• To investigate the observation of DNP in an MRFM experiment.
• To explore methods for further improving MRFM sensitivity.

Main Methods:

• A film of perdeuterated polystyrene doped with a nitroxide electron-spin probe was prepared.
• MRFM measurements were conducted at 7.3 K and ~0.6 T using a cantilever with a magnetic tip.
• The sample was irradiated with 16.7 GHz microwaves, and cantilever frequency changes were recorded.

Main Results:

• A prompt cantilever frequency change due to electron spin saturation was observed.
• A persistent cantilever frequency change was detected and tentatively attributed to polarized deuteron magnetization.
• The persistent signal's characteristics suggest a cross-effect DNP mechanism in high magnetic field gradients.

Conclusions:

• The study demonstrates the feasibility of observing DNP in MRFM experiments.
• The findings suggest that DNP can enhance MRFM sensitivity, potentially towards single spin detection.
• The observed persistent signal provides evidence for magnetization transfer from electron to deuteron spins.