Dynamic magnetostrictive response of heterostructural magnetoelectric magnetic field sensors

Abstract

Magnetoelectric (ME) heterostructural laminate composites have recently demonstrated high sensitivity room temperature operation in magnetic field sensing applications. Traditionally, a static (DC) magnetic field is applied to these sensors to enable optimal magnetostrictive response. In this thesis, the non-linear nature of the magnetostrictive response of a ME heterostructure is utilized, by applying a modulation magnetic field, to demonstrate an improvement by a factor of 11.62x in peak sensitivity and by 57.43 dB in 0-Hz signal-to-noise ratio of a sensor consisting of a longitudinally magnetized and transversely poled lamination of Metglas/PZT/Metglas layers in comparison with a conventional DC biased configuration. The ME sensor modulated by an AC magnetic field, tuned to stimulate an electro-magneto-mechanical resonance, in conjunction with a lock-in amplifier further exhibits enhanced environmental noise immunity, 1/f noise mitigation, and does not require a DC magnetic bias field. Combined, these advantages hold promise for the development of miniature ME sensor elements for size- and weight-sensitive applications.