SBIR Phase II: High-Temperature Magnetic Rotary Encoder Based on a Spintronic Sensing Array

This Small Business Innovation Research (SBIR) Phase II research project will continue the development of an incremental magnetic rotary encoder based on magnetic tunnel junction (MTJ) sensor technology. This device uses sensitive MTJ devices to sense the magnetic field created by a patterned magnetized scale, and converts the resulting information into an accurate reading of angular position. The dual advantages of high-temperature operation (up to 200 degrees C) and contamination resistance will separate this device from the optical encoders that currently dominate the market for motor encoders. Current motor encoders are rarely capable of operation above 115 degrees C, a problem that requires motors in many market segments to operate in non-optimal configurations, costing end users in terms of time and efficiency. In addition, optical methods are sensitive to dust in the measurement path. This development effort will create a new measurement technology with greatly enhanced capabilities for use in many critical segments of America's manufacturing sector. The creation of cost-effective encoders capable of operation at high temperatures will increase efficiency and enable further progress in a number of areas where hot environments are unavoidable, such as in the turbines of power-generating windmills. This research will advance the state of understanding of the emerging spintronic technology of magnetic tunnel junctions, a class of devices which forms the central component of a number of important commercial products in the high-tech semiconductor and data storage industries.