Ferromagnetism - Page 3

A study led by researchers at the University of Minnesota Twin Cities has found a property of magnetic materials that may enable engineers to develop more efficient spintronic devices in the future.

One of the main obstacles to developing better spintronic devices is an effect called “damping,” which is where the magnetic energy essentially escapes from the materials, making them less efficient. Traditionally, scientists have ascribed this property to the interaction between the electron’s spin and its motion. However, the team led by the University of Minnesota has proven that there is another factor – magnetoelastic coupling, i.e. the interaction between electron spin or magnetism and sound particles.

Researchers from Seoul National University, Pohang University of Science and Technology, Korea Atomic Energy Research Institute and the Center for Quantum Materials in Korea have designed a prototype of a non-volatile magnetic memory device entirely based on a nanometer-thin layered material, which can be tuned with a tiny current. This finding opens up a new window of opportunities for future energy-efficient magnetic memories based on spintronics.

The choice of magnetic material and device architecture depends on the fact that non-volatile memory technologies have to guarantee safe storage, but also reliable reading and writing access. Hard magnets are perfect for long-term memory storage, because they magnetize very strongly and are difficult to demagnetize. On the contrary, soft magnets are desirable for adding new information to the memory device, because their magnetization can be easily reversed during the writing process. Put simply, ideal magnetic materials can be kept at a hard magnetic state to ensure the stability of the stored information, but be soft on demand.

Researchers from the Tokyo University of Science have developed an all-solid redox device composed of magnetite (Fe₃O₄) thin film and a solid electrolyte containing lithium ions that successfully manipulated the magnetization angle at room temperature.

The researchers say they have developed a surprisingly simple yet efficient strategy to manipulate the magnetization angle in magnetite, a typical ferromagnetic material. This magnetization rotation is caused by the change of spin-orbit coupling due to electron injection into a ferromagnet. The new approach leverages a reversible electrochemical reaction.

Researchers from NYU and IBM Research have created a spintronics device from a ferromagnetic conductor and discovered that current flow in the conductor can produce a spin polarization that is in a direction set by its magnetic moment.

This discovery means that magnetic moment direction can be set in just about any desired direction to then set the spin polarization - this is not possible using the contours of the spin Hall effect in non-magnetic heavy metals.

Researchers from two FLEET universities in Australia, RMIT and UNSW, collaborated in a theoretical–experimental project that discovered a previously unseen mode of giant magneto-resistance (GMR) in 2D Fe₃GeTe₂ (FGT). This surprising result suggests a different underlying physical mechanisms in vdW hetero-structures.

The research shows that vdW materials (2D material) could offer higher functionaly cmopared to traditional spintronic approaches.

Researchers from the University of Tokyo have developed a spintronics device that can quickly and efficiently magnetize - which they say is between one and two orders of magnitude more power efficient than current spintronics device.

The researchers used a ferromagnetic semiconductor material called gallium manganese arsenide (GaMnAs) - the magnetization of which can be fully reversed with the application of very small current densities.

Researchers from the Helmholtz-Zentrum Berlin für Materialien und Energie Institute demonstrate how it is possible to induce a magnetic order on a small region of a material by using a small electric field, instead of commonly used magnetic field.

Te researchers used a wedge-shaped polycrystalline iron thin film deposited on top of a BaTiO₃ substrate (a well-known ferroelectric and ferroelastic material). Given their small size, the magnetic moments of the iron nanograins are disordered with respect to each other, this state is known as superparamagnetism.

Researchers from MIT, the Max-Born Institute, Technische Universität Berlin and the Deutsches Elektronen-Synchrotron (DESY) say ferrimagnets-based spintronics devices could be faster than ferromagnets ones.

Ferromagnets are traditional magnets - such as iron. Ferrimagnets are materials that have two types of ions with magnetic moments that are not equal - and are also polarized in opposite directions.Using these two ion types could be used, according to the researchers, to create smaller bits in magnetic memory as these will allow faster domain wall dynamics to occur.

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).

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 from the DoE's Lawrence Berkeley National Laboratory discovered that 2-D chromium germanium telluride (CGT) feature an intrinsic ferromagnetism. Up until now it was not clear whether magnetism could survive in such thin materials - but this discovery proved that it could of course.

The CGT flakes were produced using exfoliating (the scotch-tape method, the same one used to produce graphene in Manchester in 2004). This discovery can lead to extremely thin spintronic devices.