Memory - Page 6

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.

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.

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.

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.

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.

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 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.

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.

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.

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.

Researchers from Colorado State University demonstrated a new approach to store information using electron spin. Using a thin film of barium ferrite (a magnetic insulator), the researchers managed to switch magnetic moments. This is the first time an insulator was used for such an application.

This could be a major spintronics breakthrough, as an insulator material may enable simpler and more efficient storage medium. In an insulator, perpendicular magnetic anisotropy (PMA) originates from the intrinsic magneto-crystalline anisotropy of the insulator, rather than interfacial anisotropy in a metal. 

STT-MRAM is the second-generation MRAM technology, which uses spin-polarized current to flip the electron spin. STT-MRAM chips are faster, more salable and more efficient than Toggle-MRAM (first-gen MRAM tech). Several companies are now bringing STT-MRAM devices to the market.

Check out MRAM-Info's new STT-MRAM introduction article to learn more about this technology and the current market status.

Researchers from Japan's International center for Materials Nanoarchitectonics (MANA) developed a new low-current spintronic device. The device can be used to control magnetism at a lower current compared to other spintronics devices.

The new device is simple in structure, and it combines a solid electrolyte with a magnetic material. The researchers believe that such a device could in the future be used to make a high-density very low-power memory device.

Mark Stiles, from the NIST's Center for Nanoscale science and technology, gave an interesting lecture titled "Spin Current: the Torque Wrench of Spintronics" in which he discussed spintronics challenges, especially for spin-torque MRAM devices: