Researchers detect and map non-linear spin waves

Researchers from Germany's Martin Luther University Halle-Wittenberg (MLU) have demonstrated that strong alternating magnetic fields can be used to generate a new type of spin wave. This is the first time this was accomplished as the phenomenon was previously only theoretically predicted. Thee team reported on their work and provided the first microscopic images of these spin waves.

The basic idea of spintronics is to use a special property of electrons (spin) for various electronic applications. The Spin is the intrinsic angular momentum of electrons that produces a magnetic moment. Coupling these magnetic moments creates the magnetism that could ultimately be used in information processing. When these coupled magnetic moments are locally excited by a magnetic field pulse, this dynamic can spread like waves throughout the material. These are referred to as spin waves or magnons.

Read the full story Posted: Sep 16,2022

Researchers pair CrSBr magnons with excitons to "see" spins

Researchers from Columbia University, the University of Washington, New York University, and Oak Ridge National Laboratory have shown that magnons in CrSBr can pair up with another quasiparticle called an exciton, which emits light, offering the researchers a means to “see” the spinning quasiparticle.

As they perturbed the magnons with light, they observed oscillations from the excitons in the near-infrared range, which is nearly visible to the naked eye. “For the first time, we can see magnons with a simple optical effect,” said Xiaoyang Zhu from Columbia University .  

Read the full story Posted: Sep 10,2022

Researchers use QD electrodes to examine spin transport properties of DNA sensors

Scientists from India's B. P. Poddar Institute of Management & Technology, Maulana Abul Kalam Azad University of Technology and Meghnad Saha Institute of Technology, collaboration with the University of Western Australia, have used iron (Fe) quantum dot (QD) electrodes to determine the spin transport properties and quantum scattering transmission characteristics of DNA sensors at room temperature. 

Spintronics has shown great potential for the development of devices that require low power for operation, high density and high speed processing, all of which are ideal for electronic memory devices. These properties are used in optoelectronic devices, mainly for circularly polarized light. Interestingly, spintronics is also applied in a semiconductor tunnel junction.

Read the full story Posted: Sep 08,2022

Researchers investigate spin currents in chromium trihalides

Scientists have been looking for efficient methods to generate spin current. The photogalvanic effect, a phenomenon characterized by the generation of DC current from light illumination, is particularly useful in this regard. Studies have found that a photogalvanic spin current can be generated similarly using the magnetic fields in electromagnetic waves. However, there's a need for candidate materials and a general mathematical formulation for exploring this phenomenon.

Now, Associate Professor Hiroaki Ishizuka from Tokyo Institute of Technology (Tokyo Tech), along with his colleague Masahiro Sato, addressed these issues. In their recent study, they presented a general formula that can be used to calculate the photogalvanic spin current induced by transverse oscillating magnetic excitations. They then used this formula to understand how photogalvanic spin currents arise in bilayer chromium (Cr) trihalide compounds, namely chromium triiodide (CrI3) and chromium tribromide (CrBr3).

Read the full story Posted: Sep 05,2022

Researchers gain new insights into the interaction of topological insulators

An international team of researchers has succeeded in understanding, for the first time, how the topological properties of multilayer systems of Tungsten di-telluride (WTe2) can be changed systematically by means of scanning tunneling microscopy.

WTe2 has been found to be a promising material for the realization of topological states, which are regarded as the key to novel spintronics devices and quantum computers of the future due to their unique electronic properties. 

Read the full story Posted: Aug 26,2022

Researchers manage to achieve room temperature functionality of antiferromagnetic hybrids

A team of researchers, led by Igor Barsukov at the University of California, Riverside, in collaboration with researchers at Helmholtz-Zentrum Dresden-Rossendorf, the University of Utah, and the University of California, Irvine, has demonstrated efficient spin transport in an antiferromagnet/ferromagnet hybrid that remains robust up to room temperature. The researchers observed coupling of magnonic subsystems in the antiferromagnet and ferromagnet and recognized its importance in spin transport, a key process in the operation of spin-based devices. 

Antiferromagnets have zero net magnetization and are insensitive to external magnetic field perturbations. Antiferromagnetic spintronic devices hold great promise for creating future ultra-fast and energy-efficient information storage, processing, and transmission platforms, potentially leading to faster and more energy-efficient computers.  However, in order to be useful for applications impacting everyday life, the devices need to be able to operate at room temperature. One of the key factors in realizing antiferromagnetic spintronics is the injection of spin current at the antiferromagnetic interface. Previously, efficient spin injection at these interfaces was realized at cryogenic temperatures. 

Read the full story Posted: Aug 24,2022

Researchers use a multiferroic magnetoelectric material to electrically control spin currents

A research team, led by the University of California, Berkeley, recently took a step toward a spin-based computer by demonstrating a way to switch spin currents on and off electrically.

The development of devices based on pure spin currents instead of charge currents is the goal of many scientists working in spin electronics, or spintronics. A subfield of spintronics, called magnonics, focuses on devices in which these spin currents are carried specifically by magnons—wave-like disturbances of the aligned spins in a magnetic material. Magnonics researchers face a challenge in that simply exciting magnons in a material is not enough to guarantee the creation of a spin current: when the magnons are uniformly distributed, the spin current is exactly equal to zero. The magnons must be controlled, and controlling magnons in insulating materials—ones that, because of the absence of charge currents, dissipate the least amount of energy—has proven difficult. In previous experiments, researchers have sought to achieve this control using large magnetic fields, but such fields can cause collateral heating, undermining the reason for pursuing magnonics in the first place.

Read the full story Posted: Aug 16,2022

Manipulating interlayer magnetic coupling in vdW heterostructures

Researchers from FLEET at Australia's RMIT University, South China University of Technology and the Chinese Academy of Sciences (CAS) have observed electric gate-controlled exchange-bias effect in van der Waals heterostructures. The team describes this as “a promising platform for future energy-efficient, beyond-CMOS electronics”.

The exchange-bias (EB) effect, which originates from interlayer magnetic coupling, has played a significant role in fundamental magnetics and spintronics since its discovery. Although manipulating the EB effect by an electronic gate has been a significant goal in spintronics, until now, only very limited electrically-tunable EB effects have been demonstrated.

Read the full story Posted: Aug 09,2022

Researchers demonstrate spiral spin liquid on a van der Waals honeycomb magnet

Researchers at Oak Ridge National Laboratory (ORNL) have used neutron scattering to show that a spiral spin liquid is realized in the van der Waals honeycomb magnet iron trichloride (FeCl3). The ORNL team grew the host material and demonstrated this long-predicted behavior.

The team's work demonstrates that spiral spin liquids can be achieved in two-dimensional systems and provides a promising platform to study the fracton physics in spiral spin liquids. 

Read the full story Posted: Jul 29,2022

Researchers report milestone for antiferromagnetic spintronics

Researchers from the University of Tokyo and CREST (Japan Science and Technology Agency) have explored the world of spintronics and other related areas of solid state physics with a focus on antiferromagnets. The team has reported, in its recent study, the experimental realization of perpendicular and full spin–orbit torque switching of an antiferromagnetic binary state.

The team used the chiral antiferromagnet Mn3Sn, which exhibits the magnetization-free anomalous Hall effect owing to a ferroic order of a cluster magnetic octupole hosted in its chiral antiferromagnetic state. They fabricated heavy-metal/Mn3Sn heterostructures by molecular beam epitaxy and introduce perpendicular magnetic anisotropy of the octupole using an epitaxial in-plane tensile strain. By using the anomalous Hall effect as the readout, the team demonstrated 100% switching of the perpendicular octupole polarization in a 30-nanometre-thick Mn3Sn film with a small critical current density of less than 15 megaamperes per square centimeter. Their theory is that the perpendicular geometry between the polarization directions of current-induced spin accumulation and of the octupole persistently maximizes the spin–orbit torque efficiency during the deterministic bidirectional switching process. The team's recent work provides a significant basis for antiferromagnetic spintronics.

Read the full story Posted: Jul 21,2022