Microstructure and magnetic properties of sputtered spin valve systems

Different sputtering methods, viz. rf-diode, rf-magnetron, and dc-magnetron sputtering, have been used to increase the sensitivity of Co/Cu/Co/FeMn to p spin valve systems by more than a factor of 2. This improvement is due to an enhanced magnetoresistive effect DeltaR/R and a reduced anisotropy fiel d H-k for the best sample. In the present paper the transport and magnetic properties are discussed in the context of microstructure and interfacial q uality of the multilayers evaluated by comprehensive transmission electron microscopy and x-ray reflectometry investigations. The sample with the high est sensitivity (dc-magnetron sputtered) shows less structural defects and locally smoother interfaces than the other samples. Additionally it is show n that the ferromagnetic interlayer exchange field is not affected by the a pplied sputtering methods and can be well understood in terms of orange pee l coupling. (C) 2001 American Institute of Physics.