SBIR Phase I:Three-axis Vector Magnetometer with Novel Z-axis Sensor

This Small Business Innovation Research (SBIR) Phase I project will demonstrate the feasibility of combining novel nanostructured cobalt-transition metal (Co/TM, TM= Ni, Pd, Pt, Au) multilayer films with magnetic tunnel junctions (MTJs) to produce a z-axis magnetic field sensor with application to a 3-axis vector magnetometer. Nanostructured Co/TM multilayers are unique in that their magnetization direction can be tailored to be normal to the film plane. Thus an increased sensitivity to magnetic fields applied along the film normal direction can be established. These materials have readily tunable growth parameters making them ideal for a range of applications, however much of the research has focused on magnetic media with large amount of magnetic hysteresis. Here novel Co/TM-based MTJ?s will be developed and produced with the hysteresis minimized by tailoring the perpendicular anisotropy as well as sensor geometry in order to demonstrate a viable z-axis field sensor. The expected result is that sensors with sensitivity comparable to conventional ?in-plane? magnetoresistive sensors will be demonstrated and presented in connection with this technology?s incorporation into a 3-axis vector magnetometer. The broader impact/commercial potential of this project would be significant in that many areas from navigation, biomedical, security to consumer electronics would benefit from the proposed z-axis sensor and resulting single-chip 3-axis magnetometer. Current technology typically uses multi-chip or coil configurations, greatly increasing the device footprint. Otherwise, less sensitive Hall sensors are used. The novel z-axis sensor proposed here would allow for placement of a more sensitive z-axis sensor in the same package as the in-plane sensors and greatly reduce the footprint and improve performance. This is particularly critical in portable biomedical, security and consumer electronics applications that continually look to increase functionality while reducing device size. This device configuration would also reduce the required power compared to conventional AMR sensors, making a more efficient use of battery life for portable devices. The development of the magnetically soft Co/TM multilayer films required for this application could also have applications beyond vector magnetometry as the required properties are also sought after for applications such as power generation and current tunable oscillators. The technology from this project will have high commercialization potential with the obtained scientific knowledge being applicable to other areas that look to utilize nanostructured magnetic materials.