Structural, magnetotransport, and micromagnetic properties of sputtered Ir(111)/Co superlattices

This article presents a further study on the structural and magnetotransport properties in sputtered Ir(111)/Co superlattices. The magnetization loops and magnetoresistance curves show a correlation, which can be written as Delta R/R proportional to - (M/M-s)(2) and indicates that the resistive change in external magnetic field is due to spin dependent scattering of conduction electrons, although the largest Delta R/R value observed is only 4% (10 K). The low effect can be attributed to band matching between Ir and Co subbands. Annealing effects on structural and magnetic properties were observed by the results that interdiffusion of the components takes place at an annealing temperature above 350 degrees C and leads to degradation of the superlattice, followed by a decrease both in magnetic moment and in magnetoresistance. The images of Kerr microscopy and magnetic force microscopy show micromagnetic structures, which can be well understood in comparison with the magnetization and magnetoresistance measurements. (C) 2000 American Institute of Physics. [S0021-8979(00)05605-X].