Large MR ratios in spin valves bounded with insulating antiferromagnets

Abstract MR properties of spin valves composed of AF/Co/Cu/Co(/Cu/Co/AF′) layers were studied using insulating antiferromagnets, α-Fe 2 O 3 , Nio as the bottom AF and top AF′ layer. Spin valves using IrMn as the top AF′ layer were also prepared for comparison. The MR ratios of α-Fe 2 O 3 /Co/Cu/Co/Cu/Co/AF′ spin valves using Ir Mn and α-Fe 2 O 3 as the top AF’ layers were about 21% and 28%, respectively. The experimental data are compared with numerical results using the Barnas’ model. The large MR ratios in the spin valves bounded with insulating anti-ferromagnets such as α-Fe 2 O 3 may be attributed to the specular scattering effect at the interface of Co and α-Fe 2 O 3 .