Characterization of spin valve films exchange biased by Co/Ru/Co synthetic antiferromagnets prepared on 4 degree tilt-cut Si(111) wafer
Details
Spin valves exchange biased by a Co/Ru/Co [Ru/Co/Cu/Co/Ru/Co/Cu/Si Substrate] were fabricated on 4 degree tilt-cut Si (111) substrate by RF magnetron sputtering method. When a Cu (50Å) underlayer was deposited prior to the formation of the spin valves, Co/Ru/Co and Co layers constituting spin valves have been developed uniaxial magnetic anisotropy in the direction of Si <112>. In case of a Co/Ru/Co with the same thickness of Co[synthetic antiferromagnet], spin valves with a 25 Å Cu spacer have showed giant-magnetoresistance ratio above 5% until the external magnetic field overcame the crystal anisotropy field originated from tilt-cut Si substrate. When arrived at critical field, Co/Ru/Co has displayed spin flopping phenomena as in the antiferromagnetic material. In making the thickness of Co in a Co/Ru/Co different[synthetic ferrimagnet], above spin flopping phenomena have disappeared. Instead, thinner Co layer has first reversed its magnetization and keeped the antiparallel state with the thicker Co layer.
