Spintronics Memory

BiSb films feature a colossal spin hall effect and high electrical conductivity

Researchers from the Tokyo Institute of Technology have developed a new thin film material made from bismuth-antimony (BiSb) that is a topological insulator that simultaneously achieves a colossal spin Hall effect and high electrical conductivity.

This material could be used as the basis of spin-orbit torque MRAM (SOT-MRAM). SOT-MRAM SOT-MRAM can overcome the limitation of spin-transfer torque in MRAM memories - and provide a much faster, denser and much more efficient memory technology. Up until now, though, no suitable material that features both high electrical conductivity and a high spin hall effect was developed.

Researchers find multi-layered Co/Ni films highly desirable materials for effective spin transfer torque

Researchers from the University of Lorraine in France report that following a comprehensive characterization of multilayers of cobalt (Co) and nickel (Ni), the material holds great promise for memory applications based on spin transfer torque (STT-MRAM).

Multi layered cobalt and nickel films for spintronics

It was already shown before that Co/Ni multilayers have very good properties for spintronics applications, but up until now it wasn't clear if the films have a sufficiently large intrinsic spin polarization, which is necessary to create and maintain spin-polarized currents in spintronic devices. It was now shown that the films have a spin polarization of about 90% - which is similar to the best spintronic materials.

Researchers from Mainz University demonstrate the basic principles of ultra-fast and stable memory based on Mn2Au antiferromagnets

Researchers from Mainz University demonstrate the basic principles of ultra-fast and stable memory based on the antiferromagnet Mn2Au. Antiferromagnetic materials are challenging to manipulate and to implement a read-out process (of the Neel vector orientation on).

Crystal structure of Mn2Au with antiferromagnetically ordered magnetic moments.

Up until now, researchers were only able to use a single antiferromagnetic material - copper manganese arsenide (CuMnAs), but this material had several disadvantages. The new compound, manganese and gold (Mn2Au) offers for example ten times larger magnetoresistance and other important advantages including its non-toxic composition and the fact that it can be used even at higher temperatures.

Researchers discover a metallic antiferromagnet with a large magneto-optic Kerr effect

Researchers from the NIST in the US and the University of Tokyo have discovered a metallic antiferromagnet (Mn3Sn) that exhibits a large magneto-optic Kerr (MOKE) effect, despite a vanishingly small net magnetization at room temperature.

MOKE measurements in non-collinear antiferromagnets

Compared to ferromagnetic materials, metallic antiferromagnets allow for faster dynamics and more densely packed spintronic devices due to the weak interactions between antiferromagnetic cells. The researchers believe that such materials hold promise for future antiferromagnetic spintronic devices, where the magnetic state could transduced optically and switched either optically or by applying current.

Frustrated magnetic skyrmions may find applications in future spintronic devices

Researchers from Japan and China have discovered the exotic dynamics of frustrated magnetic skyrmions - which are different from that of magnetic skyrmions in common ferromagnetic materials. Magnetic skyrmions are very interesting for several spintronic applications, including magnetic memory and logic computing devices.

Skyrmions and antiskyrmions in a frustrated magnet photo

In conventional ferromagnetic materials, the helicity (degree of freedom) of a skyrmion cannot be effectively controlled, but the researchers found that in frustrated magnetic materials it is possible to control the skyrmion helicity by utilizing the helicity locking-unlocking transition of the material. The researcher further conclude that one can use frustrated skyrmions as a binary memory utilizing two stable Bloch-type states, where the helicity can be switched by applying current.

EU-funded project announced the first prototypes of nanoporous magnetic memories

The partners in the EU-funded SPIN-PORICS (Merging Nanoporous Materials with Energy-Efficient Spintronics) announced the first prototypes of nanoporous magnetic memories, based on copper and nickel alloys (CuNi).

The project team reported being able to achieve a 35% reduction of magnetic coercivity compared to current devices, which meets the energy consumption required to reorientate the magnetic domains which is necessary for data recording. This result is due to the nanoporous design which enables the whole film - not only the surface - to participate in the electromagnetic effect.

NIST researchers develop an efficient spin valve / memristor device

Researchers from the NIST were granted a patent for a device that combines a spin valve with a memristor (a device that is the basis of next-generation RRAM memory devices). The device can be used to turn on and off a spin channel.

The researchers say that their patented device may be a fundamental building-block in future spintronic devices as it combines the non-volatile memory in memristors with the technology of a spin valve. The intention is simple and can be used in several ways - as an on/off switch for spin currents, as an interconnect between different spintronic components and as an interface between magnetic and electronic features.

Researchers achieve magnetic switching using domain wall displacement

Researchers from Helmholtz-Zentrum Berlin managed to develop a robust and reliable magnetization switching process using domain wall displacement - without any applied field. This could lead to highly efficient spintronics memory devices.

Magnetic switching by domain wall displacement (HZB photo)

A spintronics memory design that uses tiny rings to enable two stable magnetization states - but the switching of the states usually requires a circular magnetic field. The researchers now devised a way to overcome to requirement - by using slightly displaced holes in the rings (which are thus thinner on one side), which means that a short uniaxial magnetic field pulse can switch between the two possible vortex states.

MIT and JGU researchers advance towards skyrmion-based spintronics

Researchers from MIT and the Johannes Gutenberg University Mainz (JGU) achieved the billion-fold reproducible motion of skyrmions (special spin structures) between different positions. The researchers say that this kind of process is needed to produce magnetic shift registers - and so this is a critical step towards skyrmions applications in spintronics devices.

The magnetic structure of the skyrmion (image)

Using specially design thin film structures (asymmetric multilayer devices) that exhibit broken inversion symmetry that stabilize the skyrmions. In such structures, skyrmions have a unique stability - which makes them compelling for such spintronic devices. The researchers say that those skyrmions, that can be shifted by electrical currents and move relatively undisturbed through the track, are very promising to make racetrack devices.