Development of half-metallic ultra-thin Fe/sub 3/O/sub 4/ film for new spin-transport devices

Summary form only given. TMR, GMR and MRAM devices are currently active areas of research. The MR ratio is related to the spin polarization (P) of electrons in the ferromagnetic electrodes. The most attractive materials for high P are the so-called half-metallic ferromagnets. The application requires a high Curie temperature (T/sub C/), so this limits the half-metallic material to Fe/sub 3/O/sub 4/ (T/sub C/=858 K). To apply the Fe/sub 3/O/sub 4/ film to devices, a low-temperature preparation and thinning technique are required. We fabricated a high-quality Fe/sub 3/O/sub 4/ film while satisfying both the low-thermal preparation and film thinness requirements. This maybe the first successful report of obtaining a high-quality Fe/sub 3/C/sub 4/ film under the crucial conditions of low substrate temperature (523 K) with an ultrathin film thickness (100 /spl Aring/). The film was deposited onto a MgO[100] substrate using rf-sputtering. The saturation magnetization was measured using a VSM. The crystallographic microstructure was analyzed using XRD. The resistivity and Verwey point ( Tv) were measured by a standard four terminal method.