High-Frequency CMR-B-Scalar Sensor for Pulsed Magnetic Field Measurement

To extend the frequency range of recently developed Colossal Magnetoresistance (CMR)-B-scalar sensors and to decrease the influence of induced picked-up (loop effect) voltages on the measured signal, a compensation method is used. A B-dot sensor of the same geometry as the CMR-B-scalar sensor's current leads is used for this purpose. This allowed the subtraction of the time derivative of the magnetic field signal from the total measurement signal obtained by the CMR-B-scalar sensor. This B-dot sensor is placed at a distance of only 0.25 mm from the CMR-B-scalar sensor. The signal from the B-dot sensor is measured directly using an oscilloscope and subtracted from the signal of the CMR-B-scalar sensor with an empirically determined weight factor. This allowed the investigation of the high-frequency behavior of the CMR-B-scalar sensor using an oscillating source of a magnetic field with a time-derivative equal to 1.7
${\rm T}/\mu{\rm s}$
. Using the compensation method described above, it is possible to measure the magnetic field pulses with amplitudes up to 10 T and rise times down to 3.5
$\mu{\rm s}$
with an overall accuracy of
${\sim}{10\%}$
.