Spin-Precession Organic Magnetic Sensor

SRI International, in collaboration with Professor Jing Shih of the University of California- Riverside UCR, Professor Nathan Newman of Arizona State University ASU, and Professor Edmond Nowak of the University of Delaware UD, has been funded from June 2009 through September 2012 through ONR Contract N00014-09-C-0292 to fabricate a magnetic sensor with a half-metallic ferromagnet FM contact and polymers and demonstrate its sensing capability. In this study we considered La0.7Sr0..3MnO3 LSMO and CoFe50Al25Si25 CFAS alloys for half-metallic FM contacts and poly3,4-ethylenedioxythiophene PEDOT and poly- 3hexylthiophene P3HT for polymers. Room temperature operation of this ultrasensitive device requires half-metallic ferromagnetic contacts with high Curie temperature Tc, ultra-lowmobilitypolymer with very high doping density, nano-scale trenches, successful charge and spin injection into polymers from FM half-metal contacts, and spin precession in polymers. The FM films for vertical and lateral devices were grown at UCR and ASU, respectively. Most device fabrication was carried out at SRI, while magnetic and noise measurements were performed at ASU and UD.