293 results about "Spin transfer" patented technology

A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The magnetic element includes pinned, nonmagnetic spacer, and free layers. The spacer layer resides between the pinned and free layers. The free layer can be switched using spin transfer when a write current is passed through the magnetic element. The magnetic element may also include a barrier layer, a second pinned layer. Alternatively, second pinned and second spacer layers and a second free layer magnetostatically coupled to the free layer are included. At least one free layer has a high perpendicular anisotropy. The high perpendicular anisotropy has a perpendicular anisotropy energy that is at least twenty and less than one hundred percent of the out-of-plane demagnetization energy.

A magnetic memory device for reading and writing a data state comprises at least three terminals including first, second, and third terminals. The magnetic memory device also includes a spin transfer (ST) driven element, disposed between the first terminal and the second terminal, and a readout element, disposed between the second terminal and the third terminal. The ST driven element includes a first free layer, and a readout element includes a second free layer. A magnetization direction of the second free layer in the readout element indicates a data state. A magnetization reversal of the first free layer within the ST driven element magnetostatically causes a magnetization reversal of the second free layer in the readout element, thereby recording the data state.

A method and system for providing a magnetic element and a corresponding memory are disclosed. In one aspect, the method and system include providing a dual spin tunnel / valve structure and at least one spin valve. The dual spin tunnel / valve structure includes a nonmagnetic spacer layer between a pinned layer and a free layer, another pinned layer and a barrier layer between the free layer and the other pinned layer. The free layers of the dual spin tunnel / valve structure and the spin valve are magnetostatically coupled. In one embodiment a separation layer resides between the dual spin tunnel / valve structure and the spin valve. In another aspect, the method and system include providing two dual spin valves, a spin tunneling junction there between and, in one embodiment, the separation layer. In both aspects, the magnetic element is configured to write to the free layers using spin transfer when a write current is passed through the magnetic element.

A method and system for providing a magnetic element capable of storing multiple bits is disclosed. The method and system include providing first pinned layer, a first nonmagnetic layer, a first free layer, a connecting layer, a second pinned layer, a second nonmagetic layer and a second free layer. The first pinned layer is ferromagnetic and has a first pinned layer magnetization pinned in a first direction. The first nonmagnetic layer resides between the first pinned layer and the first free layer. The first free layer being ferromagnetic and has a first free layer magnetization. The second pinned layer is ferromagnetic and has a second pinned layer magnetization pinned in a second direction. The connecting layer resides between the second pinned layer and the first free layer. The second nonmagnetic layer resides between the second pinned layer and the second free layer. The second free layer being ferromagnetic and having a second free layer magnetization. The magnetic element is configured to allow the first free layer magnetization and the second free layer magnetization to change direction due to spin transfer when a write current is passed through the magnetic element.

A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The method and system include providing a first pinned layer, a barrier layer, a free layer, a conductive nonmagnetic spacer layer, and a second pinned layer. Each pinned layer has a pinned layer easy axis. At least a portion of the pinned layer easy axis is in a perpendicular direction. The barrier layer resides between the first pinned layer and the free layer. The spacer layer is between the free layer and the second pinned layer. The free layer has a free layer easy axis, at least a portion of which is in the perpendicular direction. The magnetic element is also configured to allow the free layer to be switched due to spin transfer effect when a write current is passed through the magnetic element. Because of the perpendicular magnetization(s), the writing current for spin transfer may be significantly reduced.

A method and system for providing and utilizing a magnetic memory are described. The magnetic memory includes a plurality of magnetic storage cells. Each magnetic storage cell includes magnetic element(s) programmable due to spin transfer when a write current is passed through the magnetic element(s) and selection device(s). The method and system include driving a first current in proximity to but not through the magnetic element(s) of a portion of the magnetic storage cells. The first current generates a magnetic field. The method and system also include driving a second current through the magnetic element(s) of the portion of the magnetic storage cells. The first and second currents are preferably both driven through bit line(s) coupled with the magnetic element(s). The first and second currents are turned on at a start time. The second current and the magnetic field are sufficient to program the magnetic element(s).

A method and system for providing a magnetic element capable of being written in a reduced time using the spin-transfer effect while generating a high output signal and a magnetic memory using the magnetic element are disclosed. The magnetic element includes a ferromagnetic pinned layer, a nonmagnetic intermediate layer, and a ferromagnetic free layer. The pinned layer has a magnetization pinned in a first direction. The nonmagnetic intermediate layer resides between the pinned layer and the free layer. The free layer has a magnetization with an easy axis in a second direction. The first direction is in the same plane as the second direction and is oriented at an angle with respect to the second direction. This angle is different from zero and π radians. The magnetic element is also configured to allow the magnetization of the free layer to change direction due to spin transfer when a write current is passed through the magnetic element.

A magnetic element that can be used in a memory array having high density includes a pinned layer, a half-metallic material layer, a spacer (or a barrier) layer and a free layer. The half-metallic material layer is formed on the pinned layer and preferably has a thickness that is less than about 100 Å. The half-metallic material layer can be formed to be a continuous layer or a discontinuous on the pinned layer. The spacer (or barrier) layer is formed on the half-metallic material layer, such that the spacer (or barrier) layer is nonmagnetic and conductive (or insulating). The free layer is formed on the spacer (or barrier) layer and has a second magnetization that changes direction based on the spin-transfer effect when a write current passes through the magnetic element.

A method and system for providing a magnetic element capable of being written using spin-transfer effect while being thermally stable and a magnetic memory using the magnetic element are disclosed. The magnetic element includes a first, second and third pinned layers, first and second nonmagnetic layers, a free layer and a nonmagnetic spacer layers. The first, second and third pinned layers are ferromagnetic and have first, second and third magnetizations pinned in first, second and third directions. The first and second nonmagnetic layers include first and second diffusion barriers, respectively. The first and second nonmagnetic layers are between the first and second pinned layers and the second and third pinned layers, respectively. The first and second pinned layers and the second and third pinned layers are antiferromagnetically coupled. The nonmagnetic spacer layer is conductive and resides between the free layer and the third pinned layer. In addition, performance can be further improved by doping Co containing ferromagnetic layers with Cr and / or Pt.

A magnetic element for a high-density memory array includes a resettable layer and a storage layer. The resettable layer has a magnetization that is set in a selected direction by at least one externally generated magnetic field. The storage layer has at least one magnetic easy axis and a magnetization that changes direction based on the spin-transfer effect when a write current passes through the magnetic element. An alternative embodiment of the magnetic element includes an additional multilayer structure formed from a tunneling barrier layer, a pinned magnetic layer and an antiferromagnetic layer that pins the magnetization of the pinned layer in a predetermined direction. Another alternative embodiment of the magnetic element includes an additional multilayer structure that is formed from a tunneling barrier layer and a second resettable layer having a magnetic moment that is different from the magnetic moment of the resettable layer of the basic embodiment.

A magnetic memory cell and a magnetic memory incorporating the cell are described. The magnetic memory cell includes at least one magnetic element and at least one non-planar selection device. The magnetic element(s) are programmable using write current(s) driven through the magnetic element. The magnetic memory may include a plurality of magnetic storage cells, a plurality of bit lines corresponding to the plurality of magnetic storage cells, and a plurality of source lines corresponding to the plurality of magnetic storage cells.

A method and system for providing a magnetic memory is described. The method and system include providing a plurality of magnetic storage cells. Each of the plurality of magnetic storage cells includes a magnetic element and a selection transistor. The magnetic element may be programmed using spin transfer induced switching by a write current driven through the magnetic element. The selection transistor includes a source and a drain. The plurality of magnetic storage cells are grouped in pairs. The source of the selection transistor for one magnetic storage cell of a pair shares the source with the selection transistor for another magnetic storage cell of the pair.

A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The magnetic element includes pinned, nonmagnetic spacer, and free layers. The spacer layer resides between the pinned and free layers. The free layer can be switched using spin transfer when a write current is passed through the magnetic element. The magnetic element may also include a barrier layer, a second pinned layer. Alternatively, second pinned and second spacer layers and a second free layer magnetostatically coupled to the free layer are included. In one aspect, the free layer(s) include ferromagnetic material(s) diluted with nonmagnetic material(s) and / or ferrimagnetically doped to provide low saturation magnetization(s).

A method and system for providing a magnetic memory. The magnetic memory includes magnetic storage cells in an array, bit lines, and source lines. Each magnetic storage cell includes at least one magnetic element. The magnetic element(s) are programmable by write currents driven through the magnetic element(s). Each magnetic element has free and pinned layer(s) and a dominant spacer. The magnetic memory is configured such that either the read current(s) flow from the free layer(s) to the dominant spacer if the maximum low resistance state read current divided by the minimum low resistance state write current is greater than the maximum high resistance state read current divided by the minimum high resistance state write current or the read current(s) flow from the dominant spacer to the free layer(s) if the maximum low resistance state read current divided by the minimum low resistance state write current is less than the maximum high resistance state read current divided by the minimum high resistance state write current.

A method and system for providing a magnetic memory is described. The method and system include providing a plurality of magnetic storage cells. Each of the plurality of magnetic storage cells includes at least one magnetic element and a plurality of selection transistors. The at least one magnetic element is capable of being programmed using spin transfer induced switching by a write current driven through the at least one magnetic element. The at least one selection transistor is configured to allow the magnetic element to be alternately selected for writing and reading. Architectures for reading and writing to the magnetic storage cells are also described.

A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The magnetic element includes pinned, nonmagnetic spacer, and free layers. The spacer layer resides between the pinned and free layers. The free layer can be switched using spin transfer when a write current is passed through the magnetic element. The magnetic element may also include a barrier layer, a second pinned layer. Alternatively, second pinned and second spacer layers and a second free layer magnetostatically coupled to the free layer are included. In one aspect, the free layer(s) include ferromagnetic material(s) diluted with nonmagnetic material(s) and / or ferrimagnetically doped to provide low saturation magnetization(s).

A method and system for providing a magnetic memory is described. The method and system include providing magnetic memory cells, local and global word lines, bit lines, and source lines. Each magnetic memory cell includes a magnetic element and a selection device connected with the magnetic element. The magnetic element is programmed by first and second write currents driven through the magnetic element in first and second directions. The local word lines are connected with the selection device of and have a first resistivity. Each global word line corresponds to a portion of the local word lines and has a resistivity lower than the first resistivity. The bit lines are connected with the magnetic element. The source lines are connected with the selection device. Each source line corresponds to a more than one of the magnetic memory cells and carries the first and second write currents.

A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The magnetic element includes pinned, spacer, free, and spin barrier layers. The spacer layer is nonmagnetic and resides between the pinned and free layers. The free layer can be switched using spin transfer when a write current is passed through the magnetic element. The free layer resides between the spacer layer and the spin barrier layer. The spin barrier layer is configured to reduce an outer surface contribution to a damping constant of the free layer. In one aspect, the spin barrier layer has a high areal resistance and may substantially eliminate spin pumping induced damping. In another aspect, the magnetic element also includes a spin accumulation layer between the spin barrier and free layers. The spin accumulation layer has a high conductivity, preferably being metallic, and may have a long spin diffusion length.

A magnetic memory cell and a magnetic memory incorporating the cell are described. The magnetic memory cell includes at least one magnetic element and a plurality of unidirectional polarity selection devices. The magnetic element(s) are programmable using write current(s) driven through the magnetic element. The unidirectional polarity selection devices are connected in parallel and such that they have opposing polarities. The magnetic memory may include a plurality of magnetic storage cells, a plurality of bit lines corresponding to the plurality of magnetic storage cells, and a plurality of source lines corresponding to the plurality of magnetic storage cells.

A spin valve structure for a spintronic device is disclosed and includes a composite seed layer made of at least Ta and a metal layer having a fcc(111) or hcp(001) texture to enhance perpendicular magnetic anisotropy (PMA) in an overlying (Co / Ni)x multilayer. The (Co / Ni)x multilayer is deposited by a low power and high Ar pressure process to avoid damaging Co / Ni interfaces and thereby preserving PMA. As a result, only a thin seed layer is required. PMA is maintained even after annealing at 220° C. for 10 hours. Examples of GMR and TMR spin valves are described and may be incorporated in spin transfer oscillators and spin transfer MRAMs. The free layer is preferably made of a FeCo alloy including at least one of Al, Ge, Si, Ga, B, C, Se, Sn, or a Heusler alloy, or a half Heusler alloy to provide high spin polarization and a low magnetic damping coefficient.

A method and system for providing a magnetic element that can be used in a magnetic memory is disclosed. The magnetic element includes first pinned, spacer, free, spin barrier, and second pinned layers. The spacer layer is nonmagnetic and resides between the pinned and free layers. The free layer can be switched using spin transfer when a write current is passed through the magnetic element. The free layer resides between the spacer and spin barrier layers. The spin barrier layer is between the free and second pinned layers. The spin barrier layer is configured to reduce an outer surface contribution to the free layer damping constant. In one aspect, the spin barrier layer has a high areal resistance and may substantially eliminate spin pumping induced damping. In another aspect, the magnetic element also includes a spin accumulation layer between the spin barrier and free layers. The spin accumulation layer has a high conductivity and may have a long spin diffusion length.

A method and system for providing a magnetic element capable of being written using spin-transfer effect while generating a high output signal and a magnetic memory using the magnetic element are disclosed. The magnetic element includes a first ferromagnetic pinned layer, a nonmagnetic spacer layer, a ferromagnetic free layer, an insulating barrier layer and a second ferromagnetic pinned layer. The pinned layer has a magnetization pinned in a first direction. The nonmagnetic spacer layer is conductive and is between the first pinned layer and the free layer. The barrier layer resides between the free layer and the second pinned layer and is an insulator having a thickness allowing electron tunneling through the barrier layer. The second pinned layer has a magnetization pinned in a second direction. The magnetic element is configured to allow the magnetization of the free layer to change direction due to spin transfer when a write current is passed through the magnetic element.

A method and system for providing a magnetic memory is described. The method and system include providing a plurality of magnetic storage cells, a plurality of word lines, and a plurality of bit lines. Each of the plurality of magnetic storage cells includes a plurality of magnetic elements and at least one selection transistor. Each of the plurality of magnetic elements is capable of being programmed using spin transfer induced switching by a write current driven through the magnetic element. Each of the plurality of magnetic elements has a first end and a second end. The at least one selection transistor is coupled to the first end of each of the plurality of magnetic elements. The plurality of word lines is coupled with the plurality of selection transistors and selectively enables a portion of the plurality of selection transistors.

A method and system for providing a magnetic element are disclosed. The method and system include providing first and second pinned layers, a free layer, and first and second barrier layers between the first and second pinned layers, respectively, and the free layer. The first barrier layer is preferably crystalline MgO, which is insulating, and configured to allow tunneling through the first barrier layer. Furthermore, the first barrier layer has an interface with another layer, such as the free layer or the first pinned layer. The interface has a structure that provides a high spin polarization of at least fifty percent and preferably over eighty percent. The second barrier layer is insulating and configured to allow tunneling through the second barrier layer. The magnetic element is configured to allow the free layer to be switched due to spin transfer when a write current is passed through the magnetic element.

A method and system for providing a magnetic element are disclosed. The method and system include providing first and second pinned layers, a free layer, and first and second barrier layers between the first and second pinned layers, respectively, and the free layer. The first barrier layer is preferably crystalline MgO, which is insulating, and configured to allow tunneling through the first barrier layer. Furthermore, the first barrier layer has an interface with another layer, such as the free layer or the first pinned layer. The interface has a structure that provides a high spin polarization of at least fifty percent and preferably over eighty percent. The second barrier layer is insulating and configured to allow tunneling through the second barrier layer. The magnetic element is configured to allow the free layer to be switched due to spin transfer when a write current is passed through the magnetic element.

A method and system for providing a magnetic element is described. The magnetic element includes a first pinned layer, a first spacer layer, a free layer, a second spacer layer, and a second pinned layer. The first and second pinned layers have first and magnetizations oriented in first and second directions, respectively. The first and second spacer layers are nonferromagnetic. The first and second spacer layers are between the free layer and the first and second pinned layers, respectively. The magnetic element is configured either to allow the free layer to be switched to each of multiple states when both a unidirectional write current is passed through the magnetic element and the magnetic element is subjected to a magnetic field corresponding to the each states or to allow the free layer to be switched to each of the plurality of states utilizing a write current and an additional magnetic field that is applied from at least one of the first pinned layer and the second pinned layer substantially only if the write current is also applied.

A method and system for providing and magnetic element is disclosed. In one aspect, the magnetic element includes at least a pinned layer, a free layer, and a current confined layer residing between the pinned layer and the free layer. The pinned layer is ferromagnetic and has a first magnetization. The current confined layer has at least one channel in an insulating matrix. The channel(s) are conductive and extend through the current confined layer. The free layer is ferromagnetic and has a second magnetization. The pinned layer, the free layer, and the current confined layer are configured to allow the magnetization of the free layer to be switched using spin transfer. The magnetic element may also include other layers, including layers for spin valve(s), spin tunneling junction(s), dual spin valve(s), dual spin tunneling junction(s), and dual spin valve / tunnel structure(s).

A method and system for providing a magnetic memory is disclosed. The method and system include providing a plurality of magnetic elements and providing at least one stress-assist layer. Each of the plurality of magnetic elements is configured to be written using spin transfer. The at least one stress-assist layer is configured to exert at least one stress on at least one magnetic element of the plurality of magnetic elements during writing. The reduction of spin-transfer switching current is due to stress exerted by the stress-assist layer on the magnetic elements during writing. Stability of the magnetic memory with respect to thermal fluctuations is not compromised because the energy barrier between the two magnetization states is unchanged once the switching current is turned off.