Study of giant magnetoresistance in CoFe/Cu multilayer

Ta/buffer layer/[Co95Fe5(at%)/Cu] ×12/Co95Fe5/Ta multilayers were deposited by dc magnetron sputtering on Si/SiO2 substrate. The giant magnetoresistance (GMR) of the multilayers are strongly influenced by both the buffer layer material and the thickness of each sublayer of CoFe and Cu; and the GMR is enhanced by annealing in a magnetic field. When the thickness of CoFe layer, Cu spacer and Ni65Fe15Co20(at.%) buffer layer are 1.55 nm, 2.4 nm and 8 ran, respectively, the GMR of as-deposited multilayers reach to 7.6%, but after annealed at 250°C for 2 hours in a magnetic field of 79.6 × 103 A/m, the GMR of the multilayer further increase to 11.9%, while its hysteresis field reduces from 18.7 × 102 A/m to 796 A/m.