  A magnetoelectric surface acoustic wave (MESAW) type device based on
piezoelectric/magnetostrictive heterostructure was proposed to use as weak
magnetic field sensor. Unlike conventional magnetoelectric bulk laminates or
film stacks collecting magnetic field induced electrical charge, the MESAW
detects the shift of the center frequency, which highly depends on the magnetic
field due to the giant delta E effect and the phase velocity dispersion. The
magnetic field sensitivity can reach 10^(-11) Tesla in consideration of 100 Hz
frequency accuracy. Additionally, the unique working mechanism of MESAW allows
a broadband detection of weak magnetic field even with no bias magnetic field.
