Nuclear magnetic resonance force microscopy with a microwire rf source

Abstract

The authors use a 1.0μm wide patterned Cu wire with an integrated nanomagnetic tip to measure the statistical nuclear polarization of F19 in CaF2 by magnetic resonance force microscopy. With less than 350μW of dissipated power, the authors achieve rf magnetic fields over 4mT at 115MHz for a sample positioned within 100nm of the “microwire” rf source. A 200nm diameter FeCo tip integrated onto the wire produces field gradients greater than 105T∕m at the same position. The large rf fields from the broadband microwire enable long rotating-frame spin lifetimes of up to 15s at 4K.