Magnetic tunneling junctions with permalloy electrodes: a study of barrier, thermal annealing, and interlayer coupling

• Published in: Journal of magnetism and magnetic materials Vol. 267; no. 1; pp. 133 - 138
• Main Authors: Liu, Xiaoyong, Ren, Cong, Ritchie, Lance, Schrag, B.D., Xiao, Gang, Li, Lai-feng
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2003; Elsevier Science
• Subjects: Applied sciences; Electronics; Exact sciences and technology; Interfaces; Interlayer coupling; Junction breakdown and tunneling devices (including resonance tunneling devices); Magnetic devices; Magnetic thin film devices: magnetic heads (magnetoresistive, inductive, etc.); domain-motion devices, etc; Magnetic tunneling junctions (MTJs); Magnetoresistance; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Thermal annealing; 85.30.Mn; Magnetic tunneling junctions (MTJs); 75.70.−I; 85.70.Kh; Magnetoresistance; Thermal annealing; Interlayer coupling; Aluminium oxide; Binary compound; Magnetization; Tunnel effect; Experimental study; Iron alloy; 75.70.-.1; Inorganic compound; 85.70.Kh Interlayer coupling; Thickness; Permalloy; Transition metal alloy; Bias voltage; Exchange interaction; Magnetoresistance: Thermal annealing; High field; Oxidation; Nickel alloy; Binary alloy
• ISSN: 0304-8853
• DOI: 10.1016/S0304-8853(03)00298-1

Magnetic properties of Ni 81Fe 19/Al 2O 3/Ni 81Fe 19 tunneling junctions are studied for different Al thicknesses and plasma oxidation times. A maximal magnetoresistance of 34% is obtained with Al thickness of 20 Å. Magnetometry reveals large exchange bias fields (∼400 Oe) over a wide range of barrier thicknesses, indicating junctions of high quality. Transport measurements conducted on junctions before and after thermal annealing show a dramatic improvement in barrier quality after annealing. Interlayer coupling fields have been measured as a function of barrier thickness for different oxidation times.