Remote two-dimensional imaging of giant magnetoresistance with spatial resolution of 30μm

Modelling the sensitivity of infrared emissivity of magnetic thin films to giant magnetoresistance

“…Furthermore, the emissivity technique lends itself readily to spatial resolution using an IR camera to remotely sense changes in the IR temperature image of a magnetic multilayered material, and this can be developed into an image of GMR. Imaging GMR in this manner has been demonstrated in Co/Cu [7], synthetic spin-valve [8] and CoFe/Cu [9] multilayers, most recently with a spatial resolution of 30 mm.…”

“…Also, no consideration has yet been made of the thin-film nature of the magnetic materials being investigated, and this is addressed here by adapting a thin-film model of emissivity by Pigeat et al [10]. It is used to directly model the link between emissivity and GMR as a function of film thickness at far IR wavelengths, and is compared to the bulk-material results used in previous studies [6][7][8][9]. The spectral dependence of the emissivity effect at mid-to-far IR wavelengths is also examined using a Drude-type model of refractive index combined with the thin-film emissivity model, and an analytic interpretation at far IR wavelengths is presented.…”

Spatially resolving variations in giant magnetoresistance, undetectable with four-point probe measurements, using infrared microspectroscopy

“…Using a complementary technique, an IR camera is utilised to spatially resolve GMR across CoFe/Cu multilayers with a 30 lm resolution by measuring changes in emissivity. 6,7 However, this technique lacks the spectral information to adequately model the system.…”