Application of a novel rf coil design to the magnetic resonance force microscope

We report a rf coil design based on the Alderman–Grant coil called the modified Alderman–Grant coil (MAGC), and demonstrate its efficacy in the magnetic resonance force microscope (MRFM). The rf field of the MAGC has a magnitude comparable to that of a solenoidal coil of similar size (for the same input power) but the coil has a much smaller inductance. This is advantageous in electron spin resonance MRFM experiments which would benefit from rf frequencies in excess of 1000 MHz. The open design of the MAGC is also advantageous because it provides superior access to the sample mounted on a mechanical cantilever by the optical fiber and permanent magnet and so allows the sample to be placed at the center of the coil.