A spin-valve transistor with an epitaxial Fe/Au/Fe(001) base was formed on nGaAs, whose the transfer ratio was 10{sup}(-3) at 3 V with a more than 100 magnetocurrent ratio. Both bottom and upper Fe layers show the uniaxial anisotropy with an easy magnetization axis along the 110 direction, although the contribution of cubic anisotropy with a 100 easy axis cannot be neglected for the upper Fe layer. The transfer ratio was dependent on the thickness of the tunnel barrier, showing that the roughness of the barrier affects the ratio. The magnetocurrent ratio decreased monotonically with the emitter voltage, indicating the large contribution of inelastic scattering for hot electrons in the base. The possibility of applying spin-valve transistors to read heads in high-density magnetic recording is discussed.
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