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 T/μs. 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 μs with an overall accuracy of ~10%.