2104results about "Galvano-magnetic material selection" patented technology

A magnetoresistive element which records information by supplying spin-polarized electrons to a magnetic material, includes a first pinned layer which is made of a magnetic material and has a first magnetization directed in a direction perpendicular to a film surface, a free layer which is made of a magnetic material and has a second magnetization directed in the direction perpendicular to the film surface, the direction of the second magnetization reversing by the spin-polarized electrons, and a first nonmagnetic layer which is provided between the first pinned layer and the free layer. A saturation magnetization Ms of the free layer satisfies a relationship 0≧Ms<√{square root over ( )}{Jw / (6nAt)}. Jw is a write current density, t is a thickness of the free layer, A is a constant.

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 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 magnetic element is disclosed that has a composite free layer with a FM1 / moment diluting / FM2 configuration wherein FM1 and FM2 are magnetic layers made of one or more of Co, Fe, Ni, and B and the moment diluting layer is used to reduce the perpendicular demagnetizing field. As a result, lower resistance x area product and higher thermal stability are realized when perpendicular surface anisotropy dominates shape anisotropy to give a magnetization perpendicular to the planes of the FM1, FM2 layers. The moment diluting layer may be a non-magnetic metal like Ta or a CoFe alloy with a doped non-magnetic metal. A perpendicular Hk enhancing layer interfaces with the FM2 layer and may be an oxide to increase the perpendicular anisotropy field in the FM2 layer. The magnetic element may be part of a spintronic device or serve as a propagation medium in a domain wall motion device.

Magnetic tunnel junction magnetic device (16) for writing and reading uses a reference layer (20c) and a storage layer (20a) separated by a semiconductor or insulating layer (20b). The blocking temperature of the magnetisation of the storage layer is less than that of the reference layer. The storage layer is heated (22, 24) above the blocking temperature of its magnetisation. A magnetic field (34) is applied (26) to it orientating its magnetization with respect to that of the reference layer without modifying the orientation of the reference layer.

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.

We describe the structure and method of forming a STT-MTJ MRAM cell that utilizes transfer of spin angular momentum as a mechanism for changing the magnetic moment direction of a free layer. The device includes an IrMn pinning layer, a SyAP pinned layer, a naturally oxidized, crystalline MgO tunneling barrier layer that is formed on an Ar-ion plasma smoothed surface of the pinned layer and, in one embodiment, a free layer that comprises an amorphous layer of Co60Fe20B20. of approximately 20 angstroms thickness formed between two crystalline layers of Fe of 3 and 6 angstroms thickness respectively. The free layer is characterized by a low Gilbert damping factor and by very strong polarizing action on conduction electrons. The resulting cell has a low critical current, a high dR / R and a plurality of such cells will exhibit a low variation of both resistance and pinned layer magnetization angular dispersion.

A method for maximizing the interfacial properties of magnetoresistive sensors, such as spin valve and GMR sensors used in storage devices, comprises selecting the materials for ferromagnetic layers and for electrically conductive spacers that are interposed between the ferromagnetic layers. The electronegativities of the selected materials are substantially matched so that an absolute value of the differences in electronegativities is minimized. The conductive spacer material provides a relatively low resistivity and a large mean free path. The sensors experience greater chemical and thermal stability, are corrosion resistant, and realize an increased signal output.

A method and system for providing a magnetoresistive structure are described. The magnetoresistive structure includes a first electrode, an insertion layer, a crystalline tunneling barrier layer, and a second electrode. The first electrode includes at least a first magnetic material and boron. The crystalline tunneling barrier layer includes at least one constituent. The insertion layer has a first boron affinity. The at least one constituent of the crystalline tunneling barrier layer has at least a second boron affinity that is less than the first boron affinity. The second electrode includes at least a second magnetic material.

A method and system for providing a magnetic structure in magnetic transducer is described. The magnetic structure includes a pinned layer, a nonmagnetic spacer layer, and a free layer. The nonmagnetic spacer layer is between the pinned layer and the free layer. The free layer includes a first magnetic layer, a second magnetic layer, and a magnetic insertion layer between the first magnetic layer and the second magnetic layer. The first magnetic layer has a first magnetostriction. The second magnetic layer has a second magnetostriction opposite to the first magnetostriction. The magnetic insertion layer provides a growth texture barrier between the first magnetic layer and the second magnetic layer.

A MTJ for a spintronic device is disclosed and includes a thin composite seed layer made of at least Ta and a metal layer having fcc(111) or hcp(001) texture as in Ta / Ti / Cu to enhance perpendicular magnetic anisotropy (PMA) in an overlying laminated layer with a (CoFe / Ni)X, (Co / NiFe)X, (Co / NiCo)X, (CoFe / NiFe)X, or (CoFe / NiCo)X composition where x is from 5 to 30. In one embodiment, a CPP-TMR spin valve has one or both of a laminated free layer and laminated reference layer with the aforementioned compositions. The MTJ includes an interfacial layer made of CoFeB, CoFeB / CoFe, or CoFe / CoFeB between each laminated structure and the tunnel barrier. The laminated layers are deposited by a low power and high Ar pressure process to avoid damaging interfaces between adjoining layers. Annealing occurs at 220° C. to 400° C. A laminated layer with high PMA may also be included in one or more layers of a spin transfer oscillator.

A tunnel barrier in proximity with a layer of a rare earth element-transition metal (RE—TM) alloy forms a device that passes negatively spin-polarized current. The rare earth element includes at least one element selected from the group consisting of Gd, Tb, Dy, Ho, Er, Tm, and Yb. The RE and TM have respective sub-network moments such that the absolute magnitude of the RE sub-network moment is greater than the absolute magnitude of the TM sub-network moment. An additional layer of magnetic material may be used in combination with the tunnel barrier and the RE—TM alloy layer to form a magnetic tunnel junction. Still other layers of tunnel barrier and magnetic material may be used in combination with the foregoing to form a flux-closed double tunnel junction device.

A memory cell including information that is stored in the state of a magnetic bit (i.e. in a free layer, FL), where the FL magnetization has two stable states that may be canted (form an angle) with respect to the horizontal and vertical directions of the device is presented. The FL magnetization may be switched between the two canted states by the application of a voltage (i.e. electric field), which modifies the perpendicular magnetic anisotropy of the free layer.

A spin valve magnetoresistance sensor of a thin film magnetic head. In one embodiment, a spin valve magnetoresistance sensor is provided with a spin valve film, in which a base layer including a first base film of Ta or some other nonmagnetic metal and, on top of this, a second base film of an alloy represented by NiFeX (where X is at least one element selected from among Cr, Nb, Rh) is formed on a substrate, and on top of this are formed by layering a free magnetic layer and pinned magnetic layer arranged to enclose a nonmagnetic conductive layer, as well as an antiferromagnetic layer, the second base film has an fcc (face-centered cubic) structure and also has a (111) orientation.

It is possible to reduce a current required for spin injection writing. A magneto-resistance effect element includes: a first magnetization pinned layer; a magnetization free layer; a tunnel barrier layer; a second magnetization pinned layer whose direction of magnetization is pinned to be substantially anti-parallel to the direction of magnetization of the first magnetization pinned layer, and; a non-magnetic layer. When the second magnetization pinned layer is made of ferromagnetic material including Co, material for the non-magnetic layer is metal including at least one element selected from the group consisting of Zr, Hf, Rh, Ag, and Au; when the second magnetization pinned layer is made of ferromagnetic material including Fe, material for the non-magnetic layer is metal including at least one element selected from the group consisting of Rh, Pt, Ir, Al, Ag, and Au; and when the second magnetization pinned layer is made of ferromagnetic material including Ni, material for the non-magnetic layer is metal including at least one element selected from the group consisting of Zr, Hf, Au, and Ag.

An MTJ in an MRAM array or in a TMR read head is comprised of a capping layer with a lower inter-diffusion barrier layer, an intermediate oxygen gettering layer, and an upper metal layer that contacts a top conductor. The composite capping layer is especially useful with a moderate spin polarization free layer such as a NiFe layer with a Fe content of about 17.5 to 20 atomic %. The capping layer preferably has a Ru / Ta / Ru configuration in which the lower Ru layer is about 10 to 30 Angstroms thick and the Ta layer is about 30 Angstroms thick. As a result, a high dR / R of about 40% is achieved with low magnetostriction less than about 1.0 E−6 in an MTJ in an MRAM array. Best results are obtained with an AlOx tunnel barrier layer formed by an in-situ ROX process on an 8 to 10 Angstrom thick Al layer.

A method and system for providing a magnetic junction usable in a magnetic device are described. The magnetic junction includes a reference layer, a nonmagnetic spacer layer and a free layer. The nonmagnetic spacer layer is between the reference layer and the free layer. The magnetic junction is configured such that the free layer is switchable between a plurality of stable magnetic states when a write current is passed through the magnetic junction. A portion of the magnetic junction includes at least one magnetic substructure. The magnetic substructure includes at least one Fe layer and at least one nonmagnetic insertion layer. The at least one Fe layer shares at least one interface with the at least one nonmagnetic insertion layer. Each of the at least one nonmagnetic insertion layer consists of at least one of W, I, Hf, Bi, Zn, Mo, Ag, Cd, Os and In.

A method and system for providing a magnetic element and a memory incorporating the magnetic element is described. The method and system for providing the magnetic element include providing a pinned layer, a spacer layer, and a free layer. The free layer includes granular free layer having a plurality of grains in a matrix, the spacer layer residing between the pinned layer and the free layer. The magnetic element is configured to allow the granular free layer to be switched due to spin-transfer when a write current is passed through the magnetic element.

A magnetic device includes a magnetic reference layer with a fixed magnetization direction located either in the plane of the layer or perpendicular to the plane of the layer, a magnetic storage layer with a variable magnetization direction, a non-magnetic spacer separating the reference layer and the storage layer and a magnetic spin polarizing layer with a magnetization perpendicular to that of the reference layer, and located out of the plane of the spin polarizing layer if the magnetization of the reference layer is directed in the plane of the reference layer or in the plane of the spin polarizing layer if the magnetization of the reference layer is directed perpendicular to the plane of the reference layer. The spin transfer coefficient between the reference layer and the storage layer is higher than the spin transfer coefficient between the spin polarizing layer and the storage layer.

A magnetoresistive element includes a first underlying layer having an NaCl structure and containing a nitride orienting in a (001) plane, a first magnetic layer provided on the first underlying layer, having magnetic anisotropy perpendicular to a film surface, having an L10 structure, and containing a ferromagnetic alloy orienting in a (001) plane, a first nonmagnetic layer provided on the first magnetic layer, and a second magnetic layer provided on the first nonmagnetic layer and having magnetic anisotropy perpendicular to a film surface.

A ferromagnetic tunnel junction structure comprising a first ferromagnetic layer, a second ferromagnetic layer, and a tunnel barrier layer that is interposed between the first ferromagnetic layer and the second ferromagnetic layer, wherein the tunnel barrier layer includes a crystalline non-magnetic material having constituent elements that are similar to those of an crystalline oxide that has spinel structure as a stable phase structure; the non-magnetic material has a cubic structure having a symmetry of space group Fm-3m or F-43m in which atomic arrangement in the spinel structure is disordered; and an effective lattice constant of the cubic structure is substantially half of the lattice constant of the oxide of the spinel structure.

A magnetic tunnel junction (MTJ) includes a magnetic free layer, having a variable magnetization direction; an insulating tunnel barrier located adjacent to the free layer; a magnetic fixed layer having an invariable magnetization direction, the fixed layer disposed adjacent the tunnel barrier such that the tunnel barrier is located between the free layer and the fixed layer, wherein the free layer and the fixed layer have perpendicular magnetic anisotropy; and one or more of: a composite fixed layer, the composite fixed layer comprising a dusting layer, a spacer layer, and a reference layer; a synthetic antiferromagnetic (SAF) fixed layer structure, the SAF fixed layer structure comprising a SAF spacer located between the fixed layer and a second fixed magnetic layer; and a dipole layer, wherein the free layer is located between the dipole layer and the tunnel barrier.

A magnetoresistive random-access memory device with a magnetic tunnel junction stack having a significantly improved performance of the free layer in the magnetic tunnel junction structure. The memory device includes an antiferromagnetic structure and a magnetic tunnel junction structure disposed on the antiferromagnetic structure. The magnetic tunnel junction structure includes a reference layer and a free layer with a barrier layer sandwiched therebetween. Furthermore, a capping layer including a tantalum nitride film is disposed on the free layer of the magnetic tunnel junction structure.

A magnetic sensing element with improved magnetic detection output and a method for making the same are provided. In the magnetic sensing element, the length of an upper pinned magnetic layer an upper antiferromagnetic layer in a track width direction is larger than the length of a free magnetic layer in the track width direction. In making the magnetic sensing element, there is no need to remove side portions of the upper pinned magnetic layer and the upper antiferromagnetic layer. The materials of the upper pinned magnetic layer and the upper antiferromagnetic layer are thus prevented from redepositing on two side faces of the free magnetic layer during milling.

A MTJ for 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 / X)n or (CoX)n composition where n is from 2 to 30, X is one of V, Rh, Ir, Os, Ru, Au, Cr, Mo, Cu, Ti, Re, Mg, or Si, and CoX is a disordered alloy. A CoFeB layer 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. 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.

A magnetic tunnel junction stack is provided that includes nonmagnetic spacer layers between the free layer and the polarizer layer formed from magnesium oxide and tantalum nitride materials that balance the spin torques acting on the free layer. The design provided enables a deterministic final state for the storage layer and significantly improves the tunneling magnetoresistance value and switching characteristics of the magnetic tunnel junction for MRAM applications.

A spin transfer oscillator with a seed / SIL / spacer / FGL / capping configuration is disclosed with a composite seed layer made of Ta and a metal layer having a fcc(111) or hcp(001) texture to enhance perpendicular magnetic anisotropy (PMA) in an overlying (A1 / A2)X laminated spin injection layer (SIL). Field generation layer (FGL) is made of a high Bs material such FeCo. Alternatively, the STO has a seed / FGL / spacer / SIL / capping configuration. The SIL may include a FeCo layer that is exchanged coupled with the (A1 / A2)X laminate (x is 5 to 50) to improve robustness. The FGL may include an (A1 / A2)Y laminate (y=5 to 30) exchange coupled with the high Bs layer to enable easier oscillations. A1 may be one of Co, CoFe, or CoFeR where R is a metal, and A2 is one of Ni, NiCo, or NiFe. The STO may be formed between a main pole and trailing shield in a write head.