Improved Sensitivity and Noise in Magneto-Electric Magnetic Field Sensors by Use of Modulated AC Magnetostriction

A magnetic field sensor based on the nonlinear nature of the magnetostrictive response of a magneto-electric (ME) heterostructure has two orders of magnitude improvement in sensitivity and signal-to-noise ratio compared with a conventional dc-biased configuration. The sensor consists of a longitudinally magnetized and transversely poled lamination of iron-cobalt-boron (Metglas) and lead zirconate titanate (PZT). The ac-modulated sensor has enhanced environmental noise immunity and does not require a dc magnetic bias field. Combined, these advantages hold promise for the development of miniature ME sensor elements for applications with size and weight limitations.