Effect of junction geometry on switching field and reversal behavior in permalloy wires

We report on the magnetization reversal process and switching field behavior in permalloy (Ni/sub 80/Fe/sub 20/) wire structures investigated by magneto-optic Kerr effect (MOKE) and magnetoresistance (MR) measurements. A combination of electron beam lithography and a lift-off process has been utilized to fabricate three sets of wire structures from a 30 /spl Aring/ Au/300 /spl Aring/ Ni/sub 80/Fe/sub 20//GaAs(100) continuous film: straight wires, elbow wires, and cross wires with width w=0.5-50 /spl mu/m and length l=200 /spl mu/m. We found that the switching field and reversal behavior in the elbow and the cross wires depend upon the junction geometry, which nucleates or suppresses reverse domains according to the wire width. Consequently the junction determines the magnetization reversal process and switching field in the elbow and cross wires.