APPLICATION OF A NOVEL RF COIL DESIGN TO THE MAGNETIC-RESONANCE FORCEMICROSCOPE

We report a rf coil design based on the Alderman-Grant coil called th: modified Alderman-Grant. coil (MAGC), and demonstrate its efficacy in the magnetic resonance force microscope (MRFM). The rf field of the M AGC 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 induc tance. This is advantageous in electron spin resonance MRFM experiment s which would benefit from rf frequencies in excess of 1000 MHz. The o pen design of the MAGC is also advantageous because it provides superi or access to the sample mounted on a mechanical cantilever by the opti cal fiber and permanent magnet and so allows the sample to be placed a t the center of the coil. (C) 1996 American Institute of Physics.