Nuclear magnetic resonance force microscopy with a microwire rf source.

The authors use a 1.0 μm wide patterned Cu wire with an integrated nanomagnetic tip to measure the statistical nuclear polarization of 19F in CaF2 by magnetic resonance force microscopy. With less than 350 μW of dissipated power, the authors achieve rf magnetic fields over 4 mT at 115 MHz for a sample positioned within 100 nm of the “microwire” rf source. A 200 nm diameter FeCo tip integrated onto the wire produces field gradients greater than 105 T/m at the same position. The large rf fields from the broadband microwire enable long rotating-frame spin lifetimes of up to 15 s at 4 K. [ABSTRACT FROM AUTHOR]