Research On The Response Characteristic Of Magnetic Sensor Based On Magnetoelectric Effect

Magnetoelectric(ME) effect, as can be detected in the ME composite materials, is aphenomenon of polarization under the exerting of magnetic field, or induced magnetizationunder the exerting of electric field, which is a ME conversion. Its efficiency can bedescribed by a parameter named ME voltage coefficient. Magnetic sensors based on MEeffect, which exhibit significant application promise in the realms of accurate detection ofpico-Tesla (10-12T) and even femto-Tesla (10-15T) magnetic field such as geomagneticfield and biomagnetic field, simultaneously have excellent characters of high sensitivity andresolution, wide frequency response range, low power consumption, simple progressingtechnology and could be available at room temperature as well as realize passive detection.In this paper, taking the ME laminate composites of Push-Pull mode into consideration,the relationship between ME response characteristic and bias magnetic field as well as ACexcitation frequency was investigated. Theoretically, based on the―equivalent circuitmethod‖, the formula of ME voltage response to bias magnetic field at low frequency,which is the intrinsic property of the materials, was obtained; the ME response and relatedenergy consumption at resonant frequency were discussed. Experimentally, ME effecttesting system was established; the Push-Pull mode ME laminate sample was tested throughdynamic method. The results from both parts matched well.The highlight of this research is the test and evaluation work on the parameters of MElaminate sample related with magnetic sensors. The results showed that the triple-layer MElaminate sample of Push-Pull mode had high sensitivity and low background noise, whichmade the resolution could reach nTesla (10-9T) level, while the linearity of the ME laminatesample was to be inproved. The specialized signal processing circuit for ME sensor wasalso designed and manufactured. Based on the triple-layer ME laminate sample ofPush-Pull mode, Metglas was incorporated to obtain the five-layer ME laminate sample,which results in an enhanced ME response. The increase in Metglas thickness significantlyinfluences the ME response as well. It has been found that a five-layer ME laminate samplewith six sheets of Metglas (150μm thick) on both sides of the Terfenol-D layers had maximum magnitude of ME voltage coefficient of about1.2V/cm Oe which was notablyhigher than similar structures with other different Metglas thickness and was1.33timeslarger than the ME response of the triple-layer ME laminate sample. We can control theME response and optimal bias magnetic field of this kind of five-layer ME laminatecomposites by altering the thickness of Metglas layers, which proves practical significancein the application of ME sensor.