Design And Fabrication Of Microbridge Thin Films Magnetoelectric Sensor Based On PZT/FeCoSiB

The magnetoelectric(ME)sensors based on ME effect has the advantages of high sensitivity and resolution,room temperature working,wide frequency response range,low consumption,passive nature,and easy preparation,exhibiting a promising application in magnetic field sensors.Especially,the thin films ME sensor attracts great research interest due to small size and easily integrated.However,the clamping effect from the substrate,causing weak ME response and high resonance frequency,is a barrier for detecting weak and low frequency magnetic field.In this work,a microbridge thin films ME sensor is proposed to reduce the resonance frequency and improve the ME coefficient by thinning the substrate.The microbridge thin films ME sensor based on PZT/FeCoSiB was proposed in the work.The structure of the microbridge thin films ME sensors was studied by simulation software COMSOL.Secondly,the PZT film and FeCoSiB film with excellent piezoelectric properties and magnetic properties,were prepared by Sol-Gel and RF magnetron sputtering,respectively.Based on the work above,the microbridge thin films ME sensor was fabricated by microelectronics processing such as lithography and etching.Meanwhile,the performance of the sensors was measured.The conclusions can be drawn as follows:(1)The simulated results show that the resonance frequency has a linear relationship with the thickness of microbridge substrate,while the ME coefficient of the sensor has a negative logarithmic relationship with it.With the decrease of substrate thickness,the resonant frequency can be reduced to below 1 kHz,and the ME coefficient can be increased by two orders of magnitude.(2)Changing heat-treated temperature and annealing temperature can improve the crystallinity,surface roughness and ferroelectric properties of the PZT film.The PZT film heat-treated at 320? and annealed at 750? shows the(110)preferred orientation,minimum surface roughness and perfect ferroelectric properties.The FeCoSiB film annealed at 350 ? in magnetic field possesses minimum coercivity and pronounced magnetic field sensitivity.(3)The performances of the microbridge thin films ME sensor was measured by LabVIEW program-controlled ME test system.The results show that the ME coefficient can be improved effectively by the microbridge thin films ME sensor,which has a promising application.