Abstract: A piezomagnetometer uses a magnetoelectric composite structure, formed by alternating layers of piezoelectric and magnetostrictive material, to convert a fluctuating magnetic field directly to electric current. Strain in the magnetostrictive layers, coming from an ambient magnetic field, stresses piezoelectric layers and drives a polarization current proportional to amplitude of the ambient field. Electrically, the composite is a current source connected in parallel with a capacitor. Its simple and direct operation and solid state sensor enables constructing a small, rugged, inexpensive magnetometer that operates at an ambient temperature with high sensitivity at low power. Multiple piezomagnetometers can be incorporated into a practical detection system capable of operating at ambient temperatures and meeting the limitations presented in civilian and military operations.

Abstract: An instrument for non destructive evaluation (NDE) is called an electromagnetic microscope, formed by superconductive microprobes arrayed in parallel rows. When moved over a test piece, the array generates a scanned image of flaws, stress variations or changes in composition. Each microprobe has a drive coil a few mm in radius that encircles pickup loops forming a concentric, coplanar gradiometer 1 mm or less in diameter, coupled to a superconducting quantum interference device (SQUID). Drive coils transmit an oscillating magnetic field that induces eddy or magnetization currents in conductive or ferromagnetic materials, respectively. The gradiometer senses distortions in paths of induced currents. The sensitivity of SQUIDs increases sensitivity, penetration depth, and spatial resolution of flaws.