The use of a thin (Ni 0.81 Fe 0.19 ) 1 Cr seed layer for obtaining high anisotropic magnetoresistance in Permalloy (Ni 0.81 Fe 0.19 ) films is reported. The process yields a high 1 of, for example, 3.2% for 120-Å-thick NiFe, without high-temperature deposition or annealing. X-ray diffraction shows that the NiFeCr seed layer causes the formation of large (111) textured grains in the Permalloy film, and that the interface between these two layers is quite smooth. These both increase the 1 and reduce the resistance in the film, which lead to the high 1 . Also discussed is the enhanced 1 and thermal stability trilayer magnetoresistive sensors using this NiFeCr instead of Ta as a spacer.

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We studied the effects of Mn concentration ( Mn ) in PtMn antiferromagnets (AFs) and the deposition temperature ( ) of PtMn in bottom PtMn spin valves. The exchange coupling field ( ua ) and the critical thickness of PtMn were found to depend strongly on Mn . Spin valves made with the optimum Mn (51%) show an ua value of around 410 Oe even with 125-Å-thick PtMn, compared to the saturation value of about 500 Oe for the spin valves with much thicker PtMn. For the dependence study, the NiFeCr-NiFe underlayer, PtMn AF layer, and part of the CoFe pinned layer were deposited at up to 300 C, and the rest of the layers were deposited after cooling the spin valve down to ambient temperature. The spin valves deposited at 250 C and with 150-Å-thick PtMn show ua of around 250 Oe, as deposited (without postannealing). The ua values increase upon postannealing for the spin valves deposited at all the studied (25 C-300 C). However, the ferromagnetic coupling field () also increases with repetitive postannealing, the rate of increase being lower for the spin valves deposited at higher . The sheet resistance of PtMn spin valves was found to increase both after postannealing and with increasing , consistent with the higher resistivity observed for thin PtMn films deposited at higher . These results are attributed to the smaller grain size and the higher degree of chemical ordering for PtMn in the postannealed spin valves deposited initially at higher , as deduced from X-ray diffraction.

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