Spin-dependent two-level resistance fluctuations in underoxidized tunnel junctions

• Type: Article in International Scientific Journal
• Date: 2006

Authors

ventura, j. (Author) Other; teixeira, j. m. (Author) FCUP; pogorelov, y. g. (Author) FCUP; sousa, j. b. (Author) FCUP; Ferreira, R (Author) Other; Freitas, PP (Author) Other

Journal

Title: Journal of Applied Physics

Vol. 99

ISSN: 0021-8979

Publisher: American Institute of Physics

Indexing

ISI Web of Knowledge - 7 Citations

Scopus - 7 Citations

Other information

Authenticus ID: P-004-M8K

DOI: 10.1063/1.2150428

Abstract (EN): Magnetic tunnel junctions (MTJs) with partially oxidized 9 angstrom AlOx barriers were recently shown to have the characteristics needed for magnetoresistive sensors in high-density storage devices (tunneling magnetoresistance similar to 20%; RA similar to 0.5 Omega mu m(2)). Here we study the electrical transport in such low-resistance, underoxidized magnetic tunnel junctions. Under a low bias current, the tunnel magnetoresistance ratio reveals jumps between two closely separated levels, an effect associated with spin dependent transport through localized defects in the insulating barrier. We further show that dielectric breakdown at high applied electrical current is of an extrinsic nature. Temperature-dependent measurements of the electrical resistance (R) of MTJs (300-20 K) with extremely small oxidation times reveal a metallic-like behavior (dR/dT>0), although a large magnetoresistive ratio is still observed (16% at T=300 K and 28% at T=20 K). (C) 2006 American Institute of Physics.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 3