Thermal degradation of PtMn-pinned top spin valves

Cool, S.; Brown, H. J.; Michel, R. E.

doi:10.1109/20.908639

Cited by 2 publications

(1 citation statement)

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“…It is critical to deposit Stack B at RT since the GMR properties of the spin valves deposited at throughout the whole film stack were found to degrade with increasing and disappear completely at 175 C. This degradation is similar to the thermal degradation reported previously for postannealed spin valves [8], [9] and is probably due to a severe interdiffusion across the Cu spacer interfaces, since the interlayer fer- romagnetic coupling ( ) was found to increase rapidly with increasing . The spin valves deposited with only Stack A at already show exchange coupling, as deposited, if and the thickness of PtMn AF layer are sufficiently high.…”

Section: Resultssupporting

confidence: 62%

Effects of Mn concentration and deposition temperature on the giant magnetoresistive properties of ion-beam-deposited PtMn spin valves

et al. 2002

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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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Section: Resultssupporting

confidence: 62%