Spin valve films with PdPtMn antiferromagnetic layer fabricated using ultrahigh vacuum sputtering process

We investigated the background pressure (P/sub BG/) dependence of the unidirectional anisotropy field (H/sub ua/) of spin valve films with a PdPtMn antiferromagnetic layer fabricated by an ultrahigh vacuum (UHV) sputtering process. The H/sub ua/ increased with decreasing P/sub BG/ until P/sub BG/ reached 2/spl times/10/sup -7/ Pa. The UHV deposition, such as below 2.0/spl times/10/sup -7/ Pa of P/sub BG/, improved the fct [111] texture of PdPtMn, the fcc[111] of NiFe/CoFeB/Cu/CoFeB layers, enlarged the grains of spin valve films, and reduced an absorption of residual oxygen component into the spin valve films. Consequently, the exchange coupled CoFeB/PdPtMn layers exhibited large H/sub ua/ of 620 Oe, in spite of a quite thin PdPtMn (15 nm) as an ordered antiferromagnetic material, and the spin valve films show a large MR ratio of 7.8% and a sheet resistance change of 1.6 /spl Omega/.