THE EXCHANGE-BIASING IN THE TOP-CONFIGURATION Ni80Fe20/Ir20Mn80 SYSTEM

摘要

In this work, top-configuration exchange-biasing NiFe(y)/IrMn(90A) systems have been investigated with three different conditions: (a) the substrate temperature (Ts) was kept at room temperature (RT) only, (b) T, at RT with an in-plane field (h) = 500 Oe deposition during deposition, and (c) Ts = RT with h during deposition and postdeposition annealing in the field at TA = 250°C for 1h, with the samples field cooled to RT. High resolution electron cross-sectional transmission electron microscopy (HR X-TEM) and x-ray results reveal that the IrMn (111) texturing plays a key role in the exchange-biasing field (Hex) and interfacial energy (Jk). The Hex versus y result shows that Hex increases when y decreases. Since Jk = HeXM8y, where Ms is NiFe magnetization, it is easy to derive Hex = Jk/(M8y). Therefore, if Hex is inversely proportional to y, with Jk/Ms constant, we find Hexy = constant. In short, the y dependence of Jk is similar to that of Ms for each curve. The He is inversely proportional to y because of the surface pinning effects from the Ta/NiFe and NiFe/IrMn interfaces. Finally, the optimal values for HeX and Jk are 220 Oe and 0.075 erg/cm2, respectively.