A New Method to Increase the Magnetoelectric Voltage Coefficients of Metglas/PVDF Laminate Composites

Abstract

The magnetic flux density inside a Metglas sheet is much higher than that of the applied external magnetic field due to its high magnetic permeability, which is known as the magnetic flux concentration effect. Magnetic flux concentration of Metglas as a function of its sheet aspect ratio (width/length) was investigated for Metglas/Polyvinylidene fluoride (PVDF) laminar composites. Both the simulations and experimental results suggest that the magnetic flux concentration effect is markedly enhanced when the aspect ratio of a Metglas sheet is reduced. Consequently the magnetostriction of Metglas and the magnetoelectric (ME) voltage coefficients of the laminar composites are enhanced. The ME voltage coefficient for a laminar composite with a 1 mm wide and 30 mm long Metglas sheet (25 μm thick) is 21.46 V/cm•Oe, which is much higher than those reported earlier in similar laminar composites without making use of the flux concentration effect. The results demonstrate an effective means to significantly enhance the sensitivity of the magnetostrictive/piezoelectric composites as weak magnetic field sensors.

Wireless Power Delivery Techniques for Miniature Implantable Bioelectronics

“…Metglas and Terfenol‐D, with piezomagnetic coefficients of 1000 and 57 nm A −1 respectively, are two commonly used magnetostrictive materials in magnetoelectric films. [ 77–81 ]…”

“…These ME devices also have slightly improved alignment tolerance due to the fact that the magnetostrictive layer helps to capture and concentrate the magnetic field along the length of the implant. [ 16,78 ] However, this magnetostrictive layer may also cause issues with MRI compatibility in future devices. In addition, data uplink has yet to be demonstrated, and it may be challenging to develop a passive backscatter mechanism like what has been shown for NIC, RF, and US uplinks.…”