EMEmber's Blog

Magnetic Field Detector (W. Schafer)

Magnetic Field Detector (W. Schafer)

Introduction

Abstract: A current measuring method through magnetic field detection by magnetic force microscopy (MFM) was proposed and demonstrated. We observed the magnetic field around a GaAs/AlGaAs mesa stripe induced by an AC current under 10 µA. First, we pointed out the significance of elimination of the electrostatic force working between the MFM tip and the sample to obtain the magnetic force signals clearly. Then we found that the amplitudes of magnetic force signals increased with increase of the current, and that the magnetic force signals also depended on the MFM tip magnetization directions.

Researchers at the National Institute of Standards and Technology (NIST) have developed a new type of magnetometer--or magnetic-field detector--that rivals the sensitivity of its predecessors but is small and cheap, and uses very little power.

Magnetometers have a wide range of potential applications: where there is an electrical current, there is a magnetic field. Measurements of magnetic fields can reveal information about the electrical activity of the human heart and brain, the chemical identity of a spinning atom, or simply the presence or absence of metal. Because of their small size and sensitivity, the new sensors promise to improve detection of bombs and fetal heartbeats, and could be incorporated into future magnetic resonance imaging (MRI) scanners.