Low frequency noise in Co/Al2O3〈Si〉/Py magnetic tunnel junctions

✍ Scribed by Guerrero, R. ;Aliev, F. G. ;Villar, R. ;Santos, T. ;Moodera, J.

• Book ID: 105364655
• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 326 KB
• Volume: 205
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200776455

✦ Synopsis

Abstract

Low frequency noise and dynamic tunneling resistance have been studied in Co(80 Å)/Al~2~O~3~(12 Å)/Py(100 Å) magnetic tunnel junctions (MTJs) with and without asymmetric Si doping of the insulating barrier (Si ≤ 1.8 Å). Variation of the dynamic resistance and tunneling resistance with Si doping and applied bias in these MTJs indicate a transition from the Si‐doped regime to Si cluster formation above a δ ‐layer thickness of about 1.2 Å, close to 1 monolayer coverage. The measurements show anomalously strong enhancements of the low frequency noise for Si thickness above 1.2 Å, mainly due to the appearance of random telegraph noise. A simple model, which considers suppression of Coulomb blockade in the array of Si dots, opening two‐step tunnel channels, qualitatively explains the variation of both conductivity and noise with Si content. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)