International Business Machines Corporation

Samsung Electronics Co., Ltd.

Infineon Technologies Ag

Mahesh Govind Samant

Jaewoo Jeong

Stuart S P Parkin

Stuart Stephen Papworth Parkin

Yari Ferrante

Panagiotis Charilaos Filippou

Chirag Garg

Ikhtiar

Joachim Stohr

Christopher O Lada

Sampath Purushothaman

James L Speidell

Alessandro Cesare Callegari

Woojin Kim

Praveen Chaudhari

James Patrick Doyle

James Andrew Lacey

David Jame Altknecht

Keewon Kim

See-Hun Yang

Naga Phani B Aetukuri

Shui-Chin Alan Lien

Robert E Erickson

Joachim St&ouml;hr

Dmytro Apalkov

Dieter Klaus Weller

Wolfgang Raberg

Ulrich Karl Klostermann

Charles Thomas Rettner

Gary Miles McClelland

Arunava Gupta

Stephen L Brown

Xin Jiang

Shuhichi Odahara

Yoshiki Nakagawa

Sergey Faleev

S P Stuart Parkin

Fnu Ikhtiar

Sergey V Faleev

Cheng-Han Yang

Yoshimine Katoh

Ikhtiar Ikhtiar

A device is provided. The device includes a multi-layered structure that is non-magnetic at room temperature, the multi-layered structure comprising alternating layers of Co and E, wherein E comprises at least one other element selected from the group consisting of Ge, Ga, Sn and Al, wherein a composition of the multi-layered structure is represented by CoE, with x being in a range from 0.42 to 0.55. The device also includes a combined layer provided in contact with the multi-layered structure, the combined layer including an insertion layer comprising Co or Fe or Mn or Al in contact with a Heusler compound.

Tuning perpendicular magnetic anisotropy of Heusler compound in MRAM devices

A magnetic random access memory (MRAM) stack, a method of fabricating a MRAM stack, a MRAM array, and a computer system. The MRAM stack includes a first magnetic layer comprising a Heusler compound. The MRAM stack also includes one or more seed layers including a templating structure having a crystalline structure configured to template the Heusler compound. The magnetic layer is formed over the templating structure. The MRAM stack also includes a chromium (Cr) layer formed under the templating structure. The Cr layer is configured to enhance a tunnel magnetoresistance (TMR) of the MRAM stack.

Seed layer for enhancing tunnel magnetoresistance with perpendicularly magnetized Heusler films

A magnetoresistive random-access memory cell includes a templating layer. The templating layer includes a binary alloy having an alternating layer lattice structure. The cell further includes a half metallic half-Heusler layer including a half metallic half-Heusler material having a tetragonal lattice structure. The half metallic half-Heusler layer is located outward of the templating layer, and has a half-Heusler in-plane lattice constant that is different from an in-plane lattice constant in a cubic form of the half metallic half-Heusler material. A tunnel barrier is located outward of the half metallic half-Heusler layer, and a magnetic layer is located outward of the tunnel barrier.

Tetragonal half metallic half-Heusler compounds

Methods and apparatuses are provided for MRAM devices utilizing spin transfer torque. A device includes a substrate; an MTJ formed over the substrate, the MTJ including a reference layer, a tunnel barrier layer, and a free layer; and a PSM layer formed over the free layer of the MTJ. The PSM layer, i.e., a chiral material layer, may be formed adject to a free layer (or adjacent to a TBL, which is adjacent to the free layer) of the MTJ, providing an additional source of spin-transfer-torque, and providing MTJ devices that are operable with lower switching current.

Magnetic tunneling junction switching with parallel spin-momentum locked spin current

A magnetic structure, a magnetic device incorporating the magnetic structure and a method for providing the magnetic structure are described. The magnetic structure includes a magnetic layer, a templating structure and a resistive insertion layer. The magnetic layer includes a Heusler compound and has a perpendicular magnetic anisotropy energy exceeding an out-of-plane demagnetization energy. The templating structure has a crystal structure configured to template at least one of the Heusler compound and the resistive insertion layer. The magnetic layer is on the templating structure. The resistive insertion layer is configured to reduce magnetic damping for the Heusler compound and allow for templating of the Heusler compound.

Insertion layers for perpendicularly magnetized Heusler layers with reduced magnetic damping

A device including a templating structure and a magnetic layer on the templating structure is described. The templating structure includes D and E. A ratio of D to E is represented by DE, with x being at least 0.4 and not more than 0.6. E includes a main constituent. The main constituent includes at least one of Al, Ga, and Ge. Further, E includes at least fifty atomic percent of the main constituent. D includes at least one constituent that includes Ir, D includes at least 50 atomic percent of the at least one constituent. The templating structure is nonmagnetic at room temperature. The magnetic layer includes at least one of a Heusler compound and an L1compound, the magnetic layer being in contact with the templating structure.

Tunable templating layers for perpendicularly magnetized Heusler films

A magnetic device and method for providing the magnetic device are disclosed. The magnetic device includes a multilayer structure and a magnetic layer. The multilayer structure includes alternating layers of A and E. A includes a first material. The first material includes at least one of Co, Ru, or Ir. The first material may include an IrCo alloy. E includes at least one other material that includes Al. The other material(s) may include an alloy selected from AlGa, AlSn, AlGe, AlGaGe, AlGaSn, AlGeSn, and AlGaGeSn. A composition of the multilayer structure is represented by AE, where x is at least 0.45 and not more than 0.55. The magnetic layer includes an Al-doped Heusler compound. The magnetic layer shares an interface with the multilayer structure.

Ferrimagnetic Heusler compounds with high spin polarization

A device including a templating structure and a magnetic layer is described. The templating structure includes D and E. A ratio of D to E is represented by DE, with x being at least 0.4 and not more than 0.6. E includes a main constituent. The main constituent includes at least one of Al, Ga, and Ge. E includes at least fifty atomic percent of the main constituent. D includes at least one constituent that includes Ir. D includes at least 50 atomic percent of the at least one constituent. The magnetic layer is on the templating structure and includes at least one of a Heusler compound and an L1compound. The magnetic layer is in contact with the templating structure and being magnetic at room temperature.

Templating layers for perpendicularly magnetized Heusler films/compounds

A method for providing a magnetic device and the magnetic device so provided are described. The magnetic device includes a magnetic layer having a surface. In some aspects, the magnetic layer is a free layer, a reference layer, or a top layer thereof. A tunneling barrier layer is deposited on the magnetic layer. At least a portion of the tunneling barrier layer adjacent to the magnetic layer is deposited at a deposition angle of at least thirty degrees from a normal to the surface of the magnetic layer. In some aspects, the deposition angle is at least fifty degrees.

Magnetic junctions having enhanced tunnel magnetoresistance and utilizing heusler compounds

A device including a multi-layered structure that includes: a first layer that includes a first magnetic Heusler compound; a second layer that is non-magnetic at room temperature and includes both Ru and at least one other element E, wherein the composition of the second layer is represented by Ru1&#x2212;xEx, with x being in the range from 0.45 to 0.55; and a third layer including a second magnetic Heusler compound. The multi-layered structure may overlay a substrate. The device may include a tunnel barrier overlying the multi-layered structure.

Heusler compounds with non-magnetic spacer layer for formation of synthetic anti-ferromagnets (SAF)

A device including a first magnetic layer, a templating structure and a second magnetic layer is described. The templating structure is on the first magnetic layer. The second magnetic layer is on the templating structure. The templating structure includes D and E. A ratio of D to E is represented by DE, with x being at least 0.4 and not more than 0.6. E includes a main constituent. The main constituent includes at least one of Al, Ga, and Ge. E includes at least fifty atomic percent of the main constituent. D includes at least one constituent that includes Ir. D includes at least 50 atomic percent of the at least one constituent. The templating structure is nonmagnetic at room temperature. At least one of the first magnetic layer and the second magnetic layer includes at least one of a Heusler compound and an L1compound.

IrAl as a non-magnetic spacer layer for formation of synthetic anti-ferromagnets (SAF) with Heusler compounds

A device is disclosed. The device includes a first magnetic layer and a tunnel barrier. The first magnetic layer has a volume uniaxial magnetic crystalline anisotropy. The magnetic moment of the first layer is substantially perpendicular to the first layer. The tunnel barrier is in proximity to the first magnetic layer. The orientation of the magnetic moment of the first magnetic layer is reversed by spin transfer torque induced by current passing between and through the first magnetic layer and the tunnel barrier.

Spin transfer torque switching of a magnetic layer with volume uniaxial magnetic crystalline anistotropy

Devices are described that include a multi-layered structure that comprises three layers. The first layer is a magnetic Heusler compound, the second layer (acting as a spacer layer) is non-magnetic at room temperature and comprises alternating layers of Ru and at least one other element E (preferably Al; or Ga or Al alloyed with Ga, Ge, Sn or combinations thereof), and the third layer is also a magnetic Heusler compound. The composition of the second layer is represented by RuE, with x being in the range from 0.45 to 0.55. An MRAM element may be constructed by forming, in turn, a substrate, the multi-layered structure, a tunnel barrier, and an additional magnetic layer (whose magnetic moment is switchable).

A device is disclosed. The device includes a tetragonal Heusler compound of the form MnCoGe, wherein 0&#x3c;x&#x2264;1, wherein Co accounts for at least 0.4 atomic percent of the Heusler compound. The device also includes a substrate oriented in the direction (001) and of the form YMn, wherein Y includes an element selected from the group consisting of Ir and Pt, and 0&#x2264;d&#x2264;4. The tetragonal Heusler compound and the substrate are in proximity with each other, thereby allowing spin-polarized current to pass from one through the other. In one aspect, the device also includes a multi-layered structure that is non-magnetic at room temperature. The structure includes alternating layers of Co and E. E includes at least one other element that includes Al. The composition of the structure is represented by CoE, with y being in the range from 0.45 to 0.55.

Tunable tetragonal ferrimagnetic heusler compound with PMA and high TMR

A device and method for providing the device are described. The device includes a substrate, a MnN layer overlying the substrate, a multi-layered structure that is non-magnetic at room temperature and a first magnetic layer. The MnN layer has 2&#x2264;x&#x2264;4.75. The multi-layered structure comprises alternating layers of Co and E, wherein E comprises at least one other element that includes Al. The composition of the multi-layered structure is represented by CoE, with x being in the range from 0.45 to 0.55. The first magnetic layer includes a Heusler compound. The first magnetic layer is in contact with the multi-layered structure and the first magnetic layer forms part of a magnetic tunnel junction.

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San Jose, CA, United States of America

Mahesh Govind Samant