Using a novel growth technique called reactive bias target ion beam deposition, the authors have prepared highly oriented VO2 thin films on Al2O3 (0001) substrates at various growth temperatures ranging from 250to550°C. The influence of the growth parameters on the microstructure and transport properties of VO2 thin films was systematically investigated. A change in electrical conductivity of 103 was measured at 341K associated with the well known metal-insulator transition (MIT). It was observed that the MIT temperature can be tuned to higher temperatures by mixing VO2 and other vanadium oxide phases. In addition, a current/electric-field induced MIT was observed at room temperature with a drop in electrical conductivity by a factor of 8. The current densities required to induce the MIT in VO2 are about 3×104A∕cm2. The switching time of the MIT, as measured by voltage pulsed measurements, was determined to be no more than 10ns.

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CoFe/FeMn, FeMn/CoFe bilayers and CoFe/FeMn/CoFe trilayers were grown in magnetic field and at room temperature. The exchange bias field H eb depends strongly on the order of depositions and is much higher at CoFe/FeMn than at FeMn/CoFe interfaces. By combining the two bilayer structures into symmetric CoFe/FeMn(tFeMn)/CoFe trilayers, H t eb and H b eb of the top and bottom CoFe layers, respectively, are both enhanced. Reducing tFeMn of the trilayers also results in enhancements of both H b eb and H t eb . These results evidence the propagation of exchange bias between the two CoFe/FeMn and FeMn/CoFe interfaces mediated by the FeMn antiferromagnetic order.

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