Effect of Nb concentration on the microstructure of Al and the magneto resistive properties of the magnetic tunnel junction with a Nb-doped Al-oxide barrier

Sung Min Park, Ha Chang Chung, Seong Rae Lee

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish
Pages (from-to)3938-3941
Number of pages4
JournalPhysica Status Solidi (A) Applications and Materials Science
Volume204
Issue number12
DOIs
Publication statusPublished - 2007 Dec 1

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Tunnel junctions
tunnel junctions
Oxides
microstructure
Microstructure
oxides
Magnetoresistance
tunnels
Tunnels
Diffraction patterns
Electric properties
Energy gap
roughness
diffraction patterns
grain size
Surface roughness
electrical properties
Annealing
annealing
Chemical analysis

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Surfaces, Coatings and Films

Cite this

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title = "Effect of Nb concentration on the microstructure of Al and the magneto resistive properties of the magnetic tunnel junction with a Nb-doped Al-oxide barrier",
abstract = "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.",
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AU - Park, Sung Min

AU - Chung, Ha Chang

AU - Lee, Seong Rae

PY - 2007/12/1

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N2 - 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.

AB - 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.

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