Micro-structural change and high temperature properties of constituent elements (Fe, Co, Mn, Cu) in spin valves containing oxide layers

Abstract

Neither the reaction mechanism of chemical elements (Mn, Fe, Co) in specular spin valves (SVs) nor the microstructures of specular SVs containing oxide layers (OXLs) at high temperatures (>250 ?C) have been identified so far. We attempted to solve these problems via secondary-ion-mass spectroscopy, xray photoelectron spectroscopy depth profile analysis, x-ray diffraction analysis and x-ray transmission electron microscopy. The chemical properties of the constituent elements in SVs and a change in the microstructure are found to be the main reasons for magneto resistance (MR) ratio degradation at high temperatures. We also found that it is not only Mn atoms but also the OXL/ferromagnetic interface, which is an intermixed region with Cu atoms, that causes MR ratio degradation at temperatures above 275 ?C. ?? 2005 IOP Publishing Ltd.