# Size and Aspect Ratio Effects on the Magnetic Properties of a Spin-Valve Multilayer by Computer Simulation

• Lim, S.H. (Thin Film Technology Research Center Korea Institute of Science and Technology) ;
• Han, S.H. (Thin Film Technology Research Center Korea Institute of Science and Technology) ;
• Shin, K.H. (Thin Film Technology Research Center Korea Institute of Science and Technology) ;
• Kim, H.J. (Thin Film Technology Research Center Korea Institute of Science and Technology)
• Published : 2000.09.01
• 43 7

#### Abstract

The change in the magnetic properties of a spin-valve multilayer with the structure IrMn (9 m)/CoFe (4 nm)/Cu (2.6 nm)/CoFe (2 nm)/NiEe (6 nm) is investigated as a function of the size and the aspect ratio. At a fixed aspect ratio (the length/width ratio) of 2, the magnetostatic interactions begin to affect the magnetic properties substantially at a spin-valve length of 5 $\mum$, and, at a length of 1 $\mum$, they become even more dominant. In the case of a fixed multilayer size (2.4 $\mum$) which is indicated by the sum of the length and the width, magnetization change occurs by continuous spin-reversal and M-H loops are characterized by no or very small hysteresis at aspect ratios smaller than unity, At aspect ratios greater than unity, magnetization change occurs by spin-flip resulting in squared hysteresis loops. A very large changes in the coercivity and the bias field is observed, and these results are explained by two separate contributions to the total magnetostatic interactions: the coercivity by the self-demagnetizing field and the bias field by the interlayer magnetostatic interaction field.

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