Anomalous bias dependence in magnetic tunnel junctions based on half-metallic with heteroepitaxial tunnel barrierGuo-Xing Miao1, 2, Gang Xiao2 and Arunava Gupta1
1 MINT center, University of Alabama - Tuscaloosa, AL 35487, USA
2 Physics Department, Brown University - Providence, RI 02912, USA
received 29 June 2009; accepted in final form 5 August 2009; published August 2009
published online 7 September 2009
We report on the anomalous bias dependence of tunneling magnetoresistance (TMR) in ( )-based magnetic tunnel junctions as a function of barrier thickness. For a relatively thin barrier, the TMR is asymmetric and exhibits sign reversal at a specific bias voltage with varying thickness due to defect mediated resonant tunneling. On the other hand, diffusive transport dominates for sufficiently thick barriers, and a diverging TMR is observed close to zero bias.
73.40.Gk - Tunneling.
72.25.-b - Spin polarized transport.
73.40.Sx - Metal-semiconductor-metal structures.
© EPLA 2009