FeN / Co / Cu / Co계 spin - valve형 다층막의 자기저항 특성

다국어 초록 (Multilingual Abstract)

The magnetoresistance characteristics of FeN/Co/Cu/Co and FeN/Co/Cu/Co/Cu/Co/FeN multilayers using ferromagnetic iron-nitrides (FeN) has been studied. The microstructure of FeN film is the mixed α-Fe and ε-Fe₃N phase on the condition that the flow rate of N₂ gas is over 0.4 sccm. The magnetoresistance effect is observed because of shape magnetic anisotropy induced by needle-shaped ε-Fe₃N phase. This magnetoresistance effect changes, because the degree that the shape magnetic anisotropy adheres to the adjacent Co pinned layer is varied according to the flow rate of N₂ gas and the thickness of FeN film. The best magnetoresistance effect is obtained on the condition that the thickness of Co free layer is 70 Å and the maximum MR ratio(%) value of 3.2 % shows in the FeN(250 Å)/Co(70 Å)/Cu(25 Å)/Co(70 Å)/Cu(25 Å)/ Co(70 Å)/ FeN(250 Å) mutilayer film which is fabricated at the N₂ gas flow rate of 0.5 sccm and the FeN film thickness of 250 Å. Four steps are observed in the magnetoresistance curve owing to this difference of coercive force, because respective magnetic layers in the multilayer possess different coercive forces. These effects observed in these mutilayer films can be expected to application to the memory device the same MRAM as can carry out simultaneously four signals.