Title :
Magnetoresistance of Co100-xFex/Al-oxide/Co 100-xFex tunnel junctions
Author :
Nakashio, Eiji ; Sugawara, Junichi ; Onoe, Seiji ; Kumagai, Seiji
Author_Institution :
Sendai Technol. Center, Sony Corp., Japan
fDate :
9/1/2000 12:00:00 AM
Abstract :
The relationship among Co100-xFex/Al-oxide/Co100-xFex tunnel junctions (x=0, 10, 25, 40 and 50) and tunneling magnetoresistance (MR) was investigated. The highest MR ratio of 40.7% was observed for Co75Fe24/Al-oxide/Co75Fe25 junctions. The MR ratios for Co75Fe24/Al-oxide/Co 75Fe25 junctions were almost constant as a function of junction area, which implies that those junctions that possess the MR ratios over 40% do not show geometrical enhancement effect on the MR ratios. After annealing at 200°C, MR ratio of 49% was obtained for the Co75Fe24/Al-oxide/Co75 Fe25 junctions. When the bias voltage was between 360 and 455 mV, the MR ratio decreased to half its value at 1 mV. MR ratio was observed over 20% at 400 mV For Co75Fe25/Al-oxide/Co75Fe25 junctions. The bias voltage dependence of MR ratio was related to the barrier height of the junctions. MR ratio decreased more slowly with increasing bias voltage for those junctions with high barrier heights
Keywords :
aluminium compounds; annealing; cobalt alloys; ferromagnetic materials; iron alloys; magnetic heads; magnetic multilayers; magnetoresistance; tunnelling; 200 degC; 360 to 455 mV; CoFe-Al2O3-CoFe; MR ratio; annealing; barrier height; bias voltage; bias voltage dependence; junction area; magnetoresistance; tunnel junctions; Annealing; Couplings; Electrical resistance measurement; Iron alloys; Magnetic materials; Magnetic tunneling; Plasma temperature; Polarization; Tunneling magnetoresistance; Voltage;
Journal_Title :
Magnetics, IEEE Transactions on
