HIGH-SENSITIVITY MAGNETOMETER BASED ON A MAGNETOELECTRIC SENSOR

Abstract

A high-sensitivity magnetometer based on new type magnetoelectric sensor was fabricated. The sensor contains a composite structure of ferromagnetic and piezoelectric layers placed inside an electromagnetic coil. Magnetoelectric effect in the structure arises due to combination of magnetostriction of the ferromagnetic layer and piezoelectricity of the piezoelectric layer. Under simultaneous action of pumping magnetic field with frequency f and dc field to be measured, the structure generates voltage harmonics with frequencies f, 2f, 3f. Amplitudes of the 1st and the 3d harmonics are linear functions of H, which is used for measurements. The field, frequency, and amplitude characteristics of the sensor were investigated. The electronics circuits used for signals processing are described. The battery powered proto-type of the magnetometer operates in the 0.1-200 mOe magnetic field range with accuracy of 0.1 mOe. The proposed magnetoelectric magnetometer may compete with fluxgate magne-tometers and find applications in geophysics, navigation, defectoscopy, and medicine.

Keywords

• magnetoelectric effect
• magnetometer
• magnetic field sensor
• magnetostriction
• piezoelectric effect
• phase-locking
• autonomous measuring devices