GaAs/AlGaAs heterostructure based micro-hall sensors and response to A.C. excitation

Ch Ravi Kumar, T. S. Abhilash, B. P.C. Rao, T. Jayakumar, G. Rajaram

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific


Hall sensors are fabricated from GaAs/AlGaAs based heterostructures. The sensors are characterized for sensitivity using A.C and D.C. excitation techniques a known magnetic field in the range of 0-100Oe. Sensitivities of the order of 1000V/AT are obtained with a low variation of 0.15% in the temperature range of 30°C-100°C. A.C excitation (30Hz to 1 kHz) for the sensor current and phase-sensitive detection of the Hall Voltage are used to eliminate thermo-emfs and its drift with a consequent improvement in data acquisition rates of >50% over that of D.C excitation. This improves scan rates in applications such as magnetic flux leakage (MFL) measurements. The sensitivity is independent of the frequency of excitation as expected; however, the zero-field Hall voltage 'offset' value is found to have small frequency dependence.

Original languageEnglish
Title of host publicationElectromagnetic Nondestructive Evaluation (XV)
EditorsB.P.C. Rao, T. Jayakumar, Baldev Raj, Krishnan Balasubramanian
PublisherIOS Press
Number of pages6
ISBN (Print)978-160750967-7
Publication statusPublished - 2012
MoE publication typeNot Eligible

Publication series

SeriesStudies in Applied Electromagnetics and Mechanics


  • A.C. excitation
  • GaAs/AlGaAs
  • Hall sensor
  • Magnetic Flux Leakage


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