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

Chris Kelley, Sarah Madeleine Thompson, Matthew Illman, Stephane LeFrancois, Paul Dumas

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Magnetorefractive infrared (IR) microspectroscopy is demonstrated to resolve spatial variations in giant magnetoresistance (GMR) and, by modelling, provide an insight into the origin of the variations. Spatial variations are shown to be masked in conventional four-point probe electrical or IR spectral measurements. IR microspectroscopy was performed at the SMIS beamline at the SOLEIL synchrotron, modified to enable measurements in magnetic fields. A GMR gradient was induced in a CoFe/Cu multilayer sample by annealing in a temperature gradient. Modelling revealed that variations in GMR at 900Oe could be attributed to local variations in interlayer coupling locally changing the switching field.
Original languageEnglish
Article number162402
Pages (from-to)1-4
Number of pages4
JournalApplied Physics Letters
Issue number16
Publication statusPublished - 16 Oct 2012

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