SBIR Phase I: Magnetic-Tunneling-Junction Sensors for Sensitive Magnetic Microscopes

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This Small Business Innovation Research Phase I project will develop magnetic tunneling junction (MTJ) sensors, specially designed and optimized for a sensitive magnetic microscope. These miniaturized sensors, by exhibiting giant magnetoresistance (GMR) and working at ambient conditions, will enable construction of a magnetic microscope for imaging, characterizing, and investigating samples that generate minute magnetic fields at microscopic levels. The microscope will "see" local field images resulting from the electrical current distribution of a Pentium chip, revealing any operational abnormality. It will map magnetic domain structures of submicron particles. Researchers can also use the microscope to investigate basic material properties such as superconductor flux-line structures and dynamics, biomagnetism, etc. MTJ sensors are expected to have properties superior to spin-valves and Hall sensors. Phase I will tackle issues critical to the microscopes development: 1) magnetic noise; 2) magnetic couplings; and 3) micromagnetics. Phase II of this project will build a prototype of a new generation of magnetic microscope.MTJ sensors have applications in magnetic microscopy for non-invasive characterization of semiconductor chips and magnetic films and media. They can also be applied to read/write heads in data storage, remote-sensing, automotive control, electronic navigation and compassing, and non-destuctive evaluation.