Novel Materials for Ultra-Sensitive Low-Frequency Magnetometers

This work seeks to develop the ultra-low-frequency performance of spin-dependent-tunneling magnetic-field sensors through the use of novel thin-film materials to lower the frequency-dependent excess noise and increase the signal response. What is proposed is an investigation of novel thin film materials recently discovered to have high magnetoresistance effects. Magnetic sensor devices will be fabricated and their intrisinic noise spectrums will be qualitatively compared with the state-of-the-art Al2O3 barriers. Combinations of the thin-film materials and deposition conditions that prove the greatest potential for substantially increasing the sensor's signal-to-noise ratio (SNR) will be chosen for the Phase II prototype development. The goal of the program is to produce a magnetic-field sensor element which resolves sub-nanoTesla field perturbations at milliHertz frequencies. The emerging technology of spin-dependent tunneling devices is ideal in that it has great potential for increasing SNR at low frequency and its inherent attributes include: low power, small size, low cost, IC compatiblility, ruggedness, standard microelectronics processing, and broad-band frequency resolution.