Fig. 4.

Resonance shifting agent structure and fields: (a) schematic of double-disk design (for clarity, non-magnetic spacer elements not shown) showing magnetizing B₀ field (dark arrow) and resulting structure field (light arrows), (b) sample numerical calculation of the (negative) field magnitude profile in the horizontal mid-plane passing through a double-disk structure, showing uniformly shifted field magnitude between the disks, (c) sample histogram recording the magnetic field magnitudes (or equivalently, Larmor precession frequencies) surrounding a double-disk structure that shows the background water signal and the shifted spectral peak due to the double-disk structure; inset shows a blow-up around the shifted peak region. Calculations are for structures with disk radii r = 1 μm, center-to-center disk spacings 2s = 0.85 μm, and disk thickness h = 50 nm. They are assumed made from nickel with saturation magnetic polarization density of 0.6 T. (Reproduced with permission from Zabow et al., J. Micromech. Microeng. 2009)