Pressure dependence of magnetoresistance for Fe/Cr multilayers

The magnetoresistance (MR) in Fe/Cr magnetic multilayers (MML) has been measured under high pressure up to 2.5 GPa. It is found that the spin-dependent scattering plays an important role in the pressure dependence of MR ratio. In the present work, for [Fe(20Å)/Cr(10 Å)]₂₀ MML with antiferromagnetic (AF) state, the pressure coefficient of saturation field H_s is (1/H_s)(∂H_s/∂P)=3.3×10^-2 GPa^-1 between 0.1 and 2.5 GPa. We found that the (1/|J|)(∂|J|/∂P) for AF-Fe/Cr MML with polycrystalline structure is opposite in sign to that with epitaxial one. For [Fe(20 Å)/Cr(22Å)]₂₀ MML with ferromagnetic (F) state, anisotropic magnetoresistance (AMR) decreases with increasing pressure. It is suggested that the anisotropy constant decreases with weakening spin-orbit interaction at high pressure. At high field, the AMR is easily suppressed by applying pressure while the giant magnetoresistance around H_s increases slightly with increasing pressure for polycrystalline Fe/Cr MML.