Magnetoresistance studies on Co/AlOX/Au and Co/AlOX/Ni/Au tunnel structures

Summary, in English

We report on magnetoresistance (MR) studies on Co/AlOX/Au and Co/AlOX/Ni/Au magnetic tunnel junctions. In spite of the fact that the difference between the two samples is merely a 3 nm thick Ni layer, there is a sharp contrast in MR behavior indicating that the electronic structure at the interface between the ferromagnetic electrodes and the insulating barrier dominates the MR signal. The former sample exhibits a clear tunneling anisotropic MR (TAMR), with the characteristic correlation between resistance and current direction, in contrast to the latter sample which displays a conventional tunneling MR (TMR) dominated by the relative orientation between the magnetization directions of the two electrodes. In addition, the TAMR has a much stronger temperature dependence than the TMR, indicating a much faster drop-off of the tunneling density of states anisotropy than the tunneling electron spin polarization with increasing temperature. Finally, we propose a possible simple way to distinguish TAMR from normal TMR by measuring the resistance of the device at different angles of the external magnetic field.

• Author: Ruisheng Liu; C. M. Canali; Lars Samuelson; H Pettersson
• Department/s: Solid State Physics
• Publishing year: 2008
• Language: English
• Publication/Series: Applied Physics Letters
• Volume: 93
• Issue: 20
• Links: http://dx.doi.org/10.1063/1.3000614
• Document type: Journal article
• Publisher: American Institute of Physics (AIP)
• Topic: Condensed Matter Physics
• Keywords: nickel; magnetisation; tunnelling magnetoresistance; magnetic thin films; gold; ferromagnetic materials; polarisation; electron spin; cobalt; aluminium compounds; band structure
• Status: Published
• ISBN/ISSN/Other: ISSN: 0003-6951