Effect of annealing on the interfaces of giant-magnetoresistance spin-valve structures

Abstract

Si/Ta/NiFe/Cu/NiFe/FeMn/Ta spin-valve layered structures were analyzed by x-ray reflectivity, before and after annealing at 240, 320, and 360 °C. Specularly reflected x-ray data were collected using a high-resolution reflectometer and were analyzed by least-squares refinement. The thicknesses of the individual layers in the NiFe/Cu/NiFe/FeMn magnetic sandwich remained essentially unchanged. With the exception of the FeMn/Ta interface, the widths of the buried interfaces increased rapidly with annealing temperature. The increase in widths at each of the NiFe/Cu and Cu/NiFe interfaces from 6.8 to 22.6 Å caused a fivefold increase in the magnetically inactive layer in NiFe and a tenfold decrease in magnetoresistance. An increase in the total film thickness with annealing temperature was found to be caused by the surface oxidation of the Ta capping layer and the growth of a Ta silicide layer between the Ta buffer layer and the Si substrate.

Influence of stress and unidirectional field annealing on structural and magnetic performance of PtMn bottom spin-filter spin valves

“…An increase of the total film thickness with annealing temperature due to the surface oxidation of the Ta capping layer was also found by Huang et al [10]. According to [10], Ta spontaneously oxidizes to a depth of about 2.5 nm. This is consistent with the features of the in-plane XRD patterns of the sensors shown in Fig.…”

Interaction between exchange-bias systems inNi80Fe20∕Fe50Mn50∕Leung1, Blamire2 2005Phys. Rev. B

“…For significant structural changes to occur, the samples have to be annealed at high temperatures ͑200°C or more͒ for a long time ͑in the range of 1 h or more͒. 21,22 In our experiments, all of the measurements between 100 and 200°C were performed in a short time ͑less than half an hour in total͒. The effect of microstructural changes, we believe, were minimal and should not be responsible for the observed results.…”

Epitaxial growth of (111)ZrN thin films on (111)Si substrate by reactive sputtering and their surface morphologies

“…7 shows the GIXR results for this ZrN film deposited at T s ¼ 500 C, together with the fitting results. It has often been reported that good simulation fits can be achieved by ensuring that the model takes the interface layer into account [22,23]. Thus, we simulated the experimental data using a threelayer calculation model on the Si substrate that includes a surface layer on the ZrN film and a transition layer between the ZrN film and the Si substrate; the same model was used for the (0 0 1)ZrN/(0 0 1)Si system in our previous paper [11].…”