Rotating Magnetoelectric Sensor For Dc Magnetic Field Measurement

Magnetoelectric (ME) sensors have a significant potential for detection of weak magnetic fields if the mechanical resonance is utilized. Generally, magnetic and electric modulations can be employed for frequency conversion during dc or small ac signal measurements. In this paper, we perform frequency conversion using a rotating ME sensor, which enables us to detect a dc magnetic field without any additional excitation. The sensor, consisted of L-T mode ME laminates whose magnetostrictive layers are magnetized along the length directions but piezoelectric layers are poled along the thickness directions, is more sensitive to a magnetic field along its longitudinal direction. By rotation, the dc magnetic field to be measured generates a sinusoid component in the direction of the sensor's longitudinal axis, which is equivalent to applying an excitation. The experimental results are consistent with the theoretical calculations and demonstrate the feasibility of this proposed modulation method.