Stoichiometric films of bismuth titanate, Bi4Ti3O12, have been grown for the first time by the technique of pulsed excimer laser deposition. Ferroelectric films were obtained at temperatures as low as 500 °C on Si(100), MgO(110), and Pt-coated Si(100) substrates. Hysteresis measurements using a Pt-coated Si sample yielded a saturation polarization value of about 28 μC/cm2, consistent with a randomly oriented titanate film structure. A preliminary metal-insulator-semiconductor sandwich structure of the form Bi4Ti3O12-CaF2(100 Å)-Si was grown and used to examine polarization induced memory switching effects.
The temperature dependence of the afterglow decay of electrons and ions from microwave discharges in nitrogen-neon gas mixtures has been studied using combined microwave and mass-spectrometric techniques. Under conditions where N2 + is the only significant afterglow ion species, i.e., at nitrogen pressures less than 10~2 Torr, and for neon pressures in the range 15 to 40 Torr, the afterglow is controlled by the recombination of N 2 + ions and electrons. Over the temperature range studied, 205 to 480°K, the recombination coefficients exhibit no significant temperature dependence and can be represented by the constant value a(N2 + ) = (2.7±0.3)X10~7 cm 3 /sec. At any given temperature the results show no systematic dependence on the nitrogen or neon gas pressure over the ranges indicated. Temporal mass analysis indicates similar decay rates for the N2" 1 " ions and for the electrons over the major portion of the afterglow.
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