Perpendicular giant magnetoresistance of microstructures in Fe/Cr and Co/Cu multilayers (invited)

We discuss the fabrication and microstructuring techniques of pillar structures made of high vacuum sputtered Fe/Cr multilayers and of molecular beam epitaxy evaporated Co/Cu multilayers, for which we measured the giant magnetoresistance effect with the current perpendicular to the multilayer plane from 4 K to 300 K. Using optical lithography and reactive ion etching techniques we obtained structures with a typical height of 0.5 μm and a width ranging between 3 and 10 μm. For both Fe/Cr and Co/Cu multilayers we find an enhanced magnetoresistance with respect to the in-plane case. The perpendicular magnetoresistance of the Fe/Cr pillars strongly decreases with temperature, while for the Co/Cu samples the temperature dependence is weaker, indicating electron-magnon scattering processes of different strength.