Method of Using Group III-V Ferromagnetic/Non-Magnetic Semiconductor Heterojunctions and Magnetodiodes

Bruce Wessels (Inventor)

Research output: Patent


Magnetic Field Sensors NU 2005-014 Inventors Bruce Wessels Steven May Abstract Northwestern researchers have developed a novel "spintronic" magnetodiode based on a III-V ferromagnetic semiconductor and a III-V nonmagnetic semiconductor heterojunction. The diodes exhibit a large junction magnetoresistance that is linearly dependent on the applied magnetic field at room temperature, offering potential for new magnetic field sensor, gaussmeter, or other magnetoresistive devices. Magnetic sensors are employed in a range of applications, including geophysical, automotive, biomedical measurement and control equipment. Recent advances in spintronic physics provide the basis for construction of new semiconductor magnetodiodes that overcome several limitations of the prior art. Thus, fabrication of an epitaxial heterojunction, formed by metal-organic vapor phase epitaxy, enables construction of a novel magnetodiode. The magnetoresistance of the junctions measured as a function of forward bias and applied magnetic field is linear at cryogenic and room temperature from 0.1 to 9 Tesla and 1.5 to 9 Tesla, respectively, and potentially higher fields. The difference between the longitudinal and transverse magnetoresistance is only 26% and 30% at 295 K and 78 K, respectively, and provides a single device capable of sensing fields in both directions. Applications Magnetic Sensors in Measurement and Analytical Equipment: geophysical, automotive and biomedical Optoelectronic Devices: magnetic field sensor, gaussmeter and other magnetoresistive devices Advantages Compatible with current semiconductor structures Capability of magnetic imaging or interference while operating linearly in high fields Sensitivity to longitudinal and transverse fields Lower power consumption Single device capable of sensing fields in both directions IP Status Issued US Patent No. 7,956,608 Marketing Contact Allan Nader, PhD Invention Manager (e) (p) 847-497-4456
Original languageEnglish
Patent number9024370
StatePublished - May 5 2015


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