We have investigated the composition dependence of magnetic tunnel junctions (MTJs) with Nb-alloyed Al-oxide (NbAlO x) and analyzed the microstructure changes and electrical property of Nb alloyed Al-oxide layer. After annealing, tunnel magnetoresistance (TMR) ratio of MTJ with Nb-alloyed Al-oxide barrier increased up to 38.5 % at 9.26 at. % Nb. As the Nb concentration increases, the grain size decreases and the microstructure becomes a dense, fine equiaxed-type structure with fine, continuous selected area diffraction (SAD) patterns, until Nb concentration reaches 9 at. %. The microstructural changes of Nb-alloyed Al layer results in smooth interface roughness, so that we could achieve a high TMR ratio. Resistance decreased from 900 Ω to 220 Ω and barrier height decreased from 1.62 eV to 0.847 eV at 9.26 at. % Nb. We speculated that the reduction of junction resistance of the MTJ with Nb-doped Al-oxide barrier was due to Nb d states formation in the band gap.
|Number of pages||4|
|Journal||Physica Status Solidi (A) Applications and Materials Science|
|Publication status||Published - 2007 Dec 1|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films