Abstract
The Co/IrMn exchange-biasing phenomenon has been studied by employing the Si(1 0 0)/Ta/Co/IrMn/Ta samples. They were made by the sputtering method with the two cases listed below: (a) depositing without an in-plane field and (b) depositing with an in-plane field, h=1500 Oe. We have investigated their exchange-biasing field (H ex ), coercivity (H c ), and crystalline structure. From the electron-diffraction-ring patterns of transmission electron microscopy (TEM) pictures, it appears the Ta seed layer may induce the following effect: the Co layer is Hexagonal (HCP) and IrMn is face-centered cubic (FCC) with (1 1 1) texturing. In the case of (a), H ex is in general very small, while in the case of (b), H ex is on the order of 50-100 Oe.At room temperature H ex may reach a maximum when IrMn thickness t AF =90 to 110 Å and then increases when t AF from 110 to 150 Å. We conclude that the IrMn (1 1 1) structure is an important factor in governing the exchange-biasing field. © 2006 Elsevier B.V. All rights reserved.