Magnetic Oxide Films on Silicon Substrates for Sensor Applications

There is a significant market for magnetoresistive sensors as read heads for ultra high density magentic information storage, with potentially large defense and commercial applications. The recently discovered colossal magentoresistance (CMR) effects in (La, Ca) Mn O3 abd related manganite oxide systems indicate a good potential for such applications. The maximum magnetoresistance achievable ina the manganite oxides (+50%) is larger compared to that in metallic multilayers (+20%). The current challenge is to optimize the material composition and microstructure for enhancing the low field magnetoresistance. There is a need for developing a deposition method for obtaining CMR films with desirable properties on technologically important substrates over large areas with high yields. Towards this goal, we propose in this Phase I effort, to develop a process technology based on ion beam assisted pulsed laser deposition which incorporates diagnostic tools for monitoring the growth environment. Using this method, we will deposit La 1-x (Ca, Sr, Ba)x MnO3 [0.30¿x0.33] films on (i) YSZ / CeO2 buffered (100)Si substrates to obtain epitaxial films and (ii) on Si subtrates with oriented Bi4Ti#O12 structural templates to obtain c-axis oriented CMR films. The approach yielding promising results will be further optimized for desirable film properties. Depositions will be carried out on 1-2 inch2 substrates in the Phase I feasibility study and will be scaled to ¿4 inch2 in Phase II. We will explore the potential and establish the techncial feasibility of Optical Emission Spectroscopy and Langmuir electrostatic Ion probes as laser plasma diagnostic and deposition monitor tools for obtaining desirable film properties with high yield on large area Si substrates.