Exchange biased spin-valve systems with the nominal structure: 5 × [Ta (3.5 nm)/Ni 80 Fe 20 (8 nm)/Cu (t)/Ni 80 Fe 20 (6 nm)/Fe 50 Mn 50 (10 nm)/Ta (3.5 nm)], for t = 1.0 and 1.5 nm, were dc magnetron sputtered at 5 mTorr on Si(100). Similar systems with thicker Cu layers, are of interest for magnetoresistive read heads. The maximum in magnetoresistance is attributed to antiparallel alignment of the magnetization of the two Ni 80 Fe 20 layers separated by the Cu layers. The magnetic alignment in this system as a function of field is investigated by Polarized Neutron Reflectometry (PNR), as this technique is sensitive to the magnetization as a function of depth. Rijks et al. [1] calculated the optimal orientation of the magnetization in both NiFe layers as a function of applied field. Models fitted to PNR data measured at various magnetic fields support these calculations.