Ferromagnetic resonance of micrometer-sized samples
Originally published in Journal of Applied Physics 81, 4307 (1997). DOI:10.1063/1.364810 (http://dx.doi.org/10.1063/1.364810).
Submicrometer-sized slotline and coplanar waveguide devices were used for ferromagnetic resonance (FMR) measurement on submicrometer-sized magnetic fine particles. FMR measurements were taken on individual magnetic disks, having diameters ranging from 50 to 1 μm, using either a slotline-coplanar waveguide (CPW) junction device or a coplanar waveguide transmission line junction device. The magnetic samples were etched from a 105 nm thick amorphous Fe₈₀B₁₅Si₅ film on a quartz substrate. Absorption modes, which were measured with the submicrometer-sized slotline CPW, followed the Kittel magnetic resonance model for frequencies from 1 to 20 GHz for the 1 μm diam disk. By detecting the second harmonic of the lock-in amplifier's reference signal, we have measured disk samples as small as 1 mu m in diameter. We estimated that the sensitivity is of the order of 3 x 109 spins, almost four orders of magnitude better than the sensitivity of a standard electron paramagnetic resonance system.
S. Zhang, S. A. Oliver, N. E. Israeloff, A. Widom, and C. Vittoria. "Ferromagnetic resonance of micrometer-sized samples" Electrical and Computer Engineering Faculty Publications (1997).
Available at: http://works.bepress.com/nisraeloff/1