A Ferrofluid-Based Magnetic Field Sensor

The paper presents design of a highly sensitive magneto-optic sensor based on ferrofluid sensing material A quantity of 100 ml of ferrofluid was manufactured using the charge stabilized method, which proved to be very inexpensive (#0.15 per ml) and with very high Verdet constant of 122.43times10^-3 rad T^-1 m^-1 . Virtual instrumentation was used to fully characterize this novel ferrofluid under controlled laboratory conditions. As no linear birefringence was observed, this material is found to be particularly suitable for magneto-optic sensor applications where the presence of electric field is expected. The sensor was calibrated in the frequency range up to 1.8 MHz and achieved sensitivity of 0.03 A/m was limited by the induced noise