page_title: Giant magnetoimpedance
section_title: History
hierarchical_section_title: Giant magnetoimpedance / History
caption_attribution_description: English: In-phase component of the GMI measured for a piece of an amorphous ferromagnetic material (from ref. 6).
context_page_description: Giant Magnetoimpedance is a physical effect that expresses the large variation in the electrical impedance that occurs in some materials when subjected to an external magnetic field. It should not be confused with Giant Magnetoresistance that is a totally different physical phenomenon.
context_section_description: The observation that the impedance of soft-magnetic materials was influenced by the frequency and by small amplitudes of magnetic fields was observed back in the 1930s. However, the pioneering studies were limited to frequencies of a few hundreds of Hz and the changes reported in those works were not large. Only about six decades later this phenomenon was investigated again but this time making use of ac electrical currents with frequencies of hundreds of kHz. Because of the huge variations observed in the magnetic field dependence of the magnetoimpedance it was named giant magnetoimpedance. Due to the high sensitivity of the sensors making use of the GMI they have been used in compasses, accelerometers, virus detection, biomagnetism, among other applications. General overviews on the giant magnetoimpedance effect are presented in refs.
caption: In-phase component of the GMI measured for a piece of an amorphous ferromagnetic material (From ref. 7)
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