Large tunneling magnetoresistance at room temperature using a Heusler alloy with the B2 structure

A Co2Cr0.6Fe0.4Al Heusler alloy film exhibited a B2 structure, which,was deposited using a magnetron sputtering system on a, thermally oxidized Si substrate at room temperature without any buffer layers. The film exhibited the magnetic moment of 2.04mu(B) per formula unit, nearly the integer number of Bohr magnetons, suggesting a localized nature of ferromagnetisin similar to that of many Heusler compounds, which is a necessary condition for half metallicity. A spin- valve-type tunneling junction with a Co-2(Cr, Fe)Al Heusler alloy film was fabricated using metal masks, which consists Of Co2Cr0.6Fe0.4Al(10 nm)/AlOx (1.8 nm)/CoFe (3 nm)/NiFe (5 nm)/IrMn (15 nm)/Ta (5 nm), deposited on a thermally oxidized Si substrate without a buffer layer. The junction demonstrated large tunneling magnetoresistances of 16% at room temperature and 26.5% at 5K.