TY - JOUR
T1 - Dependence of giant tunnel magnetoresistance of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions on MgO barrier thickness and annealing temperature
AU - Hayakawa, Jun
AU - Ikeda, Shoji
AU - Matsukura, Fumihiro
AU - Takahashi, Hiromasa
AU - Ohno, Hideo
PY - 2005
Y1 - 2005
N2 - We investigated the dependence of giant tunnel magnetoresistance (TMR) on the thickness of an MgO barrier and on the annealing temperature of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions deposited on SiO2/Si wafers. The resistance-area product exponentially increases with MgO thickness, indicating that the quality of MgO barriers is high in the investigated thickness range of 1.15-2.4 nm. High-resolution transmission electron microscope images show that annealing at 375°C results in the formation of crystalline CoFeB/MgO/CoFeB structures, even though CoFeB electrodes are amorphous in the as-sputtered state. The TMR ratio increases with annealing temperature and is as high as 260% at room temperature and 403% at 5 K.
AB - We investigated the dependence of giant tunnel magnetoresistance (TMR) on the thickness of an MgO barrier and on the annealing temperature of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions deposited on SiO2/Si wafers. The resistance-area product exponentially increases with MgO thickness, indicating that the quality of MgO barriers is high in the investigated thickness range of 1.15-2.4 nm. High-resolution transmission electron microscope images show that annealing at 375°C results in the formation of crystalline CoFeB/MgO/CoFeB structures, even though CoFeB electrodes are amorphous in the as-sputtered state. The TMR ratio increases with annealing temperature and is as high as 260% at room temperature and 403% at 5 K.
KW - CoFeB
KW - Crystallization
KW - Magnetic tunnel junction
KW - MgO barrier
KW - Tunnel magnetoresistance effect
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U2 - 10.1143/JJAP.44.L587
DO - 10.1143/JJAP.44.L587
M3 - Article
AN - SCOPUS:28844464505
VL - 44
SP - L587-L589
JO - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes
JF - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes
SN - 0021-4922
IS - 16-19
ER -