Near-field imaging of high-frequency magnetic fields with calorimetric cantilever probes

Calorimetric probes for near-field imaging of high-frequency (1–20GHz) magnetic fields were fabricated by depositing patterned metal structures on micromachined, dielectric multilayer cantilevers. In the presence of high-frequency magnetic fields, the metal structures are heated via the generation of eddy currents or via ferromagnetic resonance (FMR). Measurement of the resulting cantilever deflection as a function of probe position produces a map of the microwave power distribution. Comparative measurements from probes with 5 and 10μm Au rings show that the rings are the active area for eddy current generation. Probes with 10μm square permalloy patches function in both the eddy current and FMR imaging modes.