TY - JOUR
T1 - Annealing effect on low-resistance ferromagnetic tunnel junctions
AU - Ando, Yasuo
AU - Kubota, Hitoshi
AU - Hayashi, Masamitsu
AU - Kamijo, Makoto
AU - Yaoita, Kazuya
AU - Yu, Andrew Chak Chung
AU - Han, Xiu Feng
AU - Miyazaki, Terunobu
PY - 2000/10
Y1 - 2000/10
N2 - The stacking structure and fabrication process of tunnel junctions were investigated. The stacking structure of the tunnel junctions fabricated was Ta/(Cu,Pt)/Fe20Ni80/IrMn/Co75Fe25/Al- oxide/Co75Fe25/Fe20Ni80/Ta. When the Al thickness, oxidation time, and annealing temperature were 0.8 nm, 15s (10s), and 300°C (250°C), the tunnel magnetoresistance (TMR) ratio and the resistance obtained were 49% (31%) and 1.1 kΩμm2 (230Ωμm2), respectively. In order to investigate the annealing temperature dependence of the TMR ratio, the local electrical properties were measured for a Ta/Fe20Ni80/Pt/Fe20Ni80/IrMn/Co75Fe25/Al- oxide multilayer. The current image became very homogeneous after annealing at around 300°C for 1 h. The increase of the TMR ratio of the junction after annealing can be well explained by taking into account both an increase of barrier height and a decrease of barrier height fluctuation. After further annealing at above 350°C, the barrier height decreased and leakage currents were detected.
AB - The stacking structure and fabrication process of tunnel junctions were investigated. The stacking structure of the tunnel junctions fabricated was Ta/(Cu,Pt)/Fe20Ni80/IrMn/Co75Fe25/Al- oxide/Co75Fe25/Fe20Ni80/Ta. When the Al thickness, oxidation time, and annealing temperature were 0.8 nm, 15s (10s), and 300°C (250°C), the tunnel magnetoresistance (TMR) ratio and the resistance obtained were 49% (31%) and 1.1 kΩμm2 (230Ωμm2), respectively. In order to investigate the annealing temperature dependence of the TMR ratio, the local electrical properties were measured for a Ta/Fe20Ni80/Pt/Fe20Ni80/IrMn/Co75Fe25/Al- oxide multilayer. The current image became very homogeneous after annealing at around 300°C for 1 h. The increase of the TMR ratio of the junction after annealing can be well explained by taking into account both an increase of barrier height and a decrease of barrier height fluctuation. After further annealing at above 350°C, the barrier height decreased and leakage currents were detected.
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U2 - 10.1143/jjap.39.5832
DO - 10.1143/jjap.39.5832
M3 - Article
AN - SCOPUS:0034290828
SN - 0021-4922
VL - 39
SP - 5832
EP - 5837
JO - Japanese Journal of Applied Physics
JF - Japanese Journal of Applied Physics
IS - 10
ER -