Fe/Fe1-xSix multilayers show distinct antiferromagnetic (AF) coupling for a wide spacer composition range 0.50<x≤1.00. As the Si content x increases, the spacer changes from metallic to insulating and the AF coupling strength (J) is significantly enhanced from 0.05 to 1.20 erg/cm2. We have explained the temperature dependence of the coupling constants J1 and J2 in terms of the quantum interference model by taking an unknown energy difference Δ(=U-εF) as a fitting parameter, where εF is the Fermi level of Fe and U is the potential of the Fe1-xSix. The aim of the present work is to determine the quantity Δ experimentally for the insulating composition range of x>0.70. The quantity Δ was evaluated both from I-V characteristics and the temperature dependence of the resistivity with the current perpendicular to the sample plane using a crossed electrode geometry junction. It is found that the barrier height increases from 0.15 to 0.70 eV with increasing the Si content x. These values almost agree with the parameter Δ deduced from the temperature dependence of J1 and J2. This agreement supports the validity of our previous calculations based on the quantum interference model.
|ジャーナル||Journal of Applied Physics|
|出版ステータス||Published - 2000 5 1|
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