Abstract. Resistivity, DC Hall effect and transverse magnetoresistance measurements were made on polycrystalline thin films of magnetite (Fe,OJ from 104 K to room temperature. The Verwey transition is observed at Tv = 123 K, about 4 K higher than reported for bulk magnetite. The ordinary and extraordinary Hall coefficients are negative over the entire temperature range, consistent with negatively charged carriers. The extraordinary Hall coefficient exhibits a dependence on the resistivity above Tv and a p2', dependence below Tv. The magnetoresistance is negative at all temperatures and for all magnetic field strengths. The planar Hall effect signal was below the sensitivity of the present experiment.

GaAs samples were implanted with tellurium at room temperature or at 150 °C and annealed to 750 °C with an SiO2 or Si3N4 protective layer. The highest electron concentrations and brightest photoluminescence were obtained for the hot implants with a Si3N4 protective layer.

Outdiffusion, lattice location and electrical behavior of Zn, Cd, Hg and Se, Te implanted into silicon at 50 keV were investigated by backscattering and channeling effect of 1 MeVHe+ ions and by Hall effect and sheet resistivity measurements. All the species exhibited outdiffusion with thermal processing. A significant fraction of Zn, Cd and Hg, when implanted into a substrate of 350°C, occupied regular interstitial lattice sites, while 50-60 per cent of the Se and Te atoms were on substitutional lattice sites. Selenium implanted at room temperature and mercury implanted into a substrate of 350°C exhibited depth dependent lattice location. The implanted layers showed n-type behavior: the maximum value of number of carriers/cmZ was less than the number of implanted ions/cm* in all cases. The highest electrical activity was observed for Se corresponding to 25 per cent of the substitutional component.

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