摘要:
A magnetic element is disclosed wherein first and second interfaces of a free layer with a Hk enhancing layer and tunnel barrier, respectively, produce enhanced surface perpendicular anisotropy to lower switching current or increase thermal stability in a magnetic tunnel junction (MTJ). In a MTJ with a bottom spin valve configuration where the Hk enhancing layer is an oxide, the capping layer contacting the Hk enhancing layer is selected to have a free energy of oxide formation substantially greater than that of the oxide. The free layer may be a single layer or composite comprised of an Fe rich alloy such as Co20Fe60B20. With a thin free layer, the interfacial perpendicular anisotropy may dominate the shape anisotropy to generate a magnetization perpendicular to the planes of the layers. The magnetic element may be part of a spintronic device or serve as a propagation medium in a domain wall motion device.
摘要:
A spin valve sensor system and a method for fabricating the same are provided. Such spin valve sensor includes a pinned layer having a pinned layer magnetization. Also included is a free layer disposed adjacent the pinned layer. The free layer has a free layer magnetization perpendicular to the pinned layer magnetization in the absence of an external field. A pinning layer is disposed adjacent the pinned layer for fixing the pinned layer magnetization. Further included is an underlayer disposed adjacent the pinning layer. Such underlayer comprises NiFeX. Disposed adjacent the underlayer and the pinning layer is an upper layer. The upper layer comprises a material selected from the group consisting of NiFe and CoFe for increasing a GMR ratio associated with the SV sensor.
摘要:
A magnetoresistance sensor is fabricated using a sensor structure including a free layer deposited upon a lower layered structure and depositing an oxide structure overlying the free layer. The depositing of the oxide structure includes the steps of depositing a buffer layer overlying the free layer, wherein the buffer layer is a buffer-layer metal when deposited, depositing an overlayer overlying and contacting the buffer layer, the overlayer being an overlayer metallic oxide of an overlayer metal, and oxidizing the buffer layer to form a buffer layer metallic oxide.
摘要:
In a spin valve, an underlayer is made of oxygen-rich nickel oxide to enhance the giant magnetoresistive ratio (ΔR/R). The oxygen-rich nickel oxide film is made using reactive sputtering of a nickel target in an oxygen-rich sputtering atmosphere consisting substantially of pure oxygen and argon gases. The total pressure of the oxygen-rich atmosphere is reduced during the oxygen-rich nickel oxide film formation to additionally enhance the ΔR/R value. A spin valve including two adjacent oxygen-rich nickel oxide underlayers provides a higher ΔR/R ratio at a given pinning strength Hua than does a spin valve having only one oxygen-rich nickel oxide underlayer.
摘要:
A magnetic element is disclosed wherein first and second interfaces of a free layer with a Hk enhancing layer and tunnel barrier, respectively, produce enhanced surface perpendicular anisotropy to lower switching current or increase thermal stability in a magnetic tunnel junction (MTJ). In a MTJ with a bottom spin valve configuration where the Hk enhancing layer is an oxide, the capping layer contacting the Hk enhancing layer is selected to have a free energy of oxide formation substantially greater than that of the oxide. The free layer may be a single layer or composite comprised of an Fe rich alloy such as Co20Fe60B20. With a thin free layer, the interfacial perpendicular anisotropy may dominate the shape anisotropy to generate a magnetization perpendicular to the planes of the layers. The magnetic element may be part of a spintronic device or serve as a propagation medium in a domain wall motion device.
摘要:
Methods of forming magnetic memory cells are disclosed. Magnetic and non-magnetic materials are formed into a primal precursor structure in an initial stress state of essentially no strain, compressive strain, or tensile strain. A stress-compensating material, e.g., a non-sacrificial, conductive material, is formed to be disposed on the primal precursor structure to form a stress-compensated precursor structure in a net beneficial stress state. Thereafter, the stress-compensated precursor structure may be patterned to form a cell core of a memory cell. The net beneficial stress state of the stress-compensated precursor structure lends to formation of one or more magnetic regions, in the cell core, exhibiting a vertical magnetic orientation without deteriorating a magnetic strength of the one or more magnetic regions. Also disclosed are memory cells, memory cell structures, semiconductor device structures, and spin torque transfer magnetic random access memory (STT-MRAM) systems.
摘要:
An improved PMA STT MTJ storage element, and a method for forming it, are described. By inserting a suitable oxide layer between the storage and cap layers, improved PMA properties are obtained, increasing the potential for a larger Eb/kT thermal factor as well as a larger MR. Another important advantage is better compatibility with high processing temperatures, potentially facilitating integration with CMOS.
摘要:
A method for forming a MTJ in a spintronic device is disclosed and includes a thin seed layer that enhances perpendicular magnetic anisotropy (PMA) in an overlying laminated layer with a (Co/Ni)n composition. The seed layer is preferably NiCr, NiFeCr, Hf, or a composite thereof. Furthermore, a magnetic layer such as CoFeB may be formed between the laminated layer and a tunnel barrier layer to serve as a transitional layer between a (111) laminate and (100) MgO tunnel barrier. There may be a Ta insertion layer between the CoFeB layer and laminated layer to promote (100) crystallization in the CoFeB layer. The laminated layer may be used as a reference layer, dipole layer, or free layer in a MTJ. Annealing between 300° C. and 400° C. may be used to further enhance PMA in the laminated layer.
摘要:
Methods of forming magnetic memory cells are disclosed. Magnetic and non-magnetic materials are formed into a primal precursor structure in an initial stress state of essentially no strain, compressive strain, or tensile strain. A stress-compensating material, e.g., a non-sacrificial, conductive material, is formed to be disposed on the primal precursor structure to form a stress-compensated precursor structure in a net beneficial stress state. Thereafter, the stress-compensated precursor structure may be patterned to form a cell core of a memory cell. The net beneficial stress state of the stress-compensated precursor structure lends to formation of one or more magnetic regions, in the cell core, exhibiting a vertical magnetic orientation without deteriorating a magnetic strength of the one or more magnetic regions. Also disclosed are memory cells, memory cell structures, semiconductor device structures, and spin torque transfer magnetic random access memory (STT-MRAM) systems.