Static information storage and retrieval – Systems using particular element – Magnetoresistive
Patent
1996-11-27
1998-09-01
Nelms, David C.
Static information storage and retrieval
Systems using particular element
Magnetoresistive
365171, 365173, G11C 1100, G11C 1114, G11C 1115
Patent
active
058019847
ABSTRACT:
A magnetic tunnel junction device usable as a memory cell or an external magnetic field sensor uses a multilayer of ferromagnetic layers in place of a single hard high-coercivity ferromagnetic layer in one of the two magnetic tunnel junction electrodes. The magnetic tunnel junction element in the device is made up of a ferromagnetic multilayer structure that has high coercivity to maintain its magnetic moment fixed in the presence of an applied magnetic field in the range of interest, a single free ferromagnetic layer whose magnetic moment is free to rotate, and an insulating tunnel barrier layer located between and in contact with the ferromagnetic multilayer structure and the free ferromagnetic layer. The fixed ferromagnetic multilayer structure is made up of two layers, a first ferromagnetic layer with a coercivity substantially higher than the applied field and a thin ferromagnetic interface layer that exhibits high spin filtering and is located between and in contact with the first ferromagnetic layer and the insulating tunnel barrier layer. The material in the first ferromagnetic layer of the multilayer can have low magnetization and thus poor spin filtering because the spin filtering is provided by the interface layer. The interface ferromagnetic layer in the multilayer has relatively low coercivity but is kept thin so that the overall coercivity of the multilayer is not degraded.
REFERENCES:
patent: 3623038 (1971-11-01), Franklin et al.
patent: 5055158 (1991-10-01), Gallagher et al.
patent: 5432734 (1995-07-01), Kawano et al.
patent: 5640343 (1997-06-01), Gallagher et al.
patent: 5650958 (1997-07-01), Gallagher et al.
J.M. Daughton, "Magnetoresistive Memory Technology", Thin Solid Films, vol. 216, 1992, pp. 162-168.
G. R. Harp et al., "Seeded Epitaxy of Metals by Sputter Deposition", Applied Physics Letters, vol. 65, No. 24, Dec. 12, 1994, pp. 3063-3065.
M. Julliere, "Tunneling Between Ferromagnetic Films", Physics Letters, vol. 54A, No. 3, Sep. 8, 1975, pp. 225-226.
K. P. Kamper et al., "CrO.sub.2 -- A New Half-metallic ferromagnet?", Physical Review Letters, vol. 59, No. 24, Dec. 14, 1987, pp. 2788-2791.
M. B. Ketchen et al., "Sub-.mu.m Linewidth Input Coils for Low T.sub.c Integrated Thin-film DC Superconducting Quantum Interference Devices", Applied Physics Letters, vol. 61, No. 3, Jul. 20, 1992, pp. 336-338.
K. Matsuyama et al., "Fabrication of Microstructured Magnetic Tunneling Valve Junction ", IEEE Transactions on Magnetics, vol. 31, No. 6, Nov. 1995, pp. 3176-3178.
R. Meservey et al., "Spin-polarized Electron Tunneling", Physics Reports, vol. 238, No. 4, 1994, pp. 214-217.
T. Miyazaki et al., "Large Magnetoresistance Effect in 82Ni-Fe/Al-Al.sub.2 O.sub.3 /Co Magnetic Tunneling Junction", Journal of Magnetism and Magnetic Materials, vol. 98, 1991, pp. L7-L9.
T. Miyazaki et al., "Giant Magnetic Tunneling Effect in Fe/Al.sub.2 O.sub.3 /Fe Junction", Journal of Magnetism and Magnetic Materials, vol. 139, 1995, pp. L231-L234.
J. S. Moodera et al., "Variation of the Electron-spin Polarization in EuSe Tunnel Junctions From Zero to Near 100% in a Magnetic Field", Physical Review Letters, vol. 70, No. 6, Feb. 8, 1993, pp. 853-856.
J. S. Moodera et al., "Large Magnetoresistance at Room Temperature in Ferromagnetic Thin Film Tunnel Junctions", Physical Review Letters, vol. 74, No. 16, Apr. 17, 1995, pp. 3273-3276.
J. S. Moodera et al., "Ferromagnetic-insulator-ferromagnetic Tunneling: Spin-dependent Tunneling and Large Magnetoresistance in Trilayer Junctions", Journal of Applied Physics, vol. 79, No. 8, Apr. 15, 1996, pp. 4724-4729.
J. S. Moodera et al., "Geometrically Enhanced Magnetoresistance in Ferromagnet-Insulator-Ferromagnet Tunnel Junctions", Applied Physics Letters, vol. 69, No. 5, Jul. 29, 1996, pp. 708-710.
S. S. P. Parkin, "Origin of Enhanced Magnetoresistance of Magnetic Multilayers: Spin-dependent Scattering From Magnetic Interface States", Physical Review Letters, vol. 71, No. 10, Sep. 6, 1993, pp. 1641-1644.
J. C. Slonczewski, "Magnetic Bubble Tunnel Detector", IBM Technical Disclosure Bulletin, vol. 19, No. 6, Nov. 1976, pp. 2328-2330.
J. C. Slonczewski, "Magnetic-field Tunnel-sensor", IBM Technical Disclosure Bulletin, vol. 19, No. 6, Nov. 1976, pp. 2331-2332.
J. C. Slonczewski, "Magnetic-barrier Current Amplifier", IBM Technical Disclosure Bulletin, vol. 19, No. 6, Nov. 1976, pp. 2333-2336.
C. Tsang et al., "Design, Fabrication & Testing of Spin-valve Read Heads for High Density Recording", IEEE Transactions on Magnetics, vol. 30, No. 6, Nov. 1994, pp. 3801-3806.
R. Wiesendanger et al., "Observation of Vacuum Tunneling of Spin-polarized Electrons with the Scanning Tunneling Microscope", Physical Review Letters, vol. 65, No. 2, Jul. 9, 1990, pp. 247-250.
T. Yaoi et al., "Dependence of Magnetoresistance on Temperature and Applied Voltage in a 82Ni-Fe/Al-Al.sub.2 O.sub.3 /Co Tunneling Junction", Journal of Magnetism and Magnetic Materials, vol. 126, 1993, pp. 430-432.
Berthold Thomas R.
International Business Machines - Corporation
Nelms David C.
Phan Trong
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