Thermal stability study of the insulator layer in NiFe/CoFe/Al2O3/CO spin-dependent tunnel junction
Journal
Journal of Magnetism and Magnetic Materials
Journal Volume
239
Journal Issue
44929
Pages
116-119
Date Issued
2002
Author(s)
URI
Abstract
Spin-dependent tunnel junction, NiFe/CoFe/Al2O3/Co//Si, was fabricated to investigate the thermal stability induced diffusion behaviors. The interfacial diffusion causes the degradation of the ratio of the TMR, the enhancement of the switching field of the two magnetic electrodes, the thickness decrease of the insulator layer, and the increase of the interfacial roughness. The outward diffusion of oxygen from the insulator layer is faster than that of aluminum for samples annealed below 400°C. The degradation of the ratio of TMR is attributed to the disturbance of the spin polarization in the magnetic layers, and the increase of the pinholes and spin-flip effect in the insulator layer. The relative roughness between the two interfaces of the insulator induces the surface magnetic dipoles, and hence, increases the switching field of the ferromagnetic electrodes. © 2002 Elsevier Science B.V. All rights reserved.
Subjects
Interfacial roughness; Spin polarization; Thermal stability; Tunneling magnetoresistance
Other Subjects
Annealing; Diffusion; Electric insulators; Electrodes; Interfaces (materials); Magnetic moments; Magnetoresistance; Polarization; Surface roughness; Thermodynamic stability; Tunneling magnetoresistance (TMR); Tunnel junctions
Type
journal article