Recent Spintronic News - Page 3

Researchers from Osaka University, Japan Science and Technology Agency (JST) and Tokyo Institute of Technology have developed copolymer films that interact differently with currents with opposite polarization. 

Despite their identical composition, molecules that are mirror images can interact differently with light and electrical current depending on their chirality. In a recent study, the research team produced spin-coated chiral copolymer films that display strong spin polarization, which enables the films to act as "spin filters" that behave differently toward currents with opposite polarization directions.

Researchers from Delft University of Technology and Karlsruhe Institute of Technology (KIT) have initiated a controlled movement in the heart of an atom, causing the atomic nucleus to interact with one of the electrons in the outermost shells of the atom. This electron could be manipulated and read out through the needle of a scanning tunneling microscope. The research offers prospects for storing quantum information inside the nucleus, where it is safe from external disturbances.

The team studied a single titanium atom - a Ti-47 atom, that has one neutron less than the naturally abundant Ti-48, which makes the nucleus slightly magnetic. This magnetism, or the 'spin', can be seen as a sort of compass needle that can point in various directions. The orientation of the spin at a given time constitutes a piece of quantum information.

Researchers from Monash University, part of the FLEET Centre, and China's Weifang University, have reported a generic approach towards intrinsic magnetic second-order topological insulators - materials that can be beneficial for spintronics.

Two-dimensional ferromagnetic semiconductors, such as CrI₃, Cr₂Ge₂Te₆, and VI₃, have been extensively studied in recent years and are fundamental to spintronics. Topological insulators are materials with unique properties where the interior is insulating, but the boundary can conduct electrons. In three-dimensional topological insulators like Bi₂Se₃, the surface hosts two-dimensional Dirac fermions. Second-order topological insulators, a new concept extending the idea of topological insulators, exhibit (m-2)-dimensional boundary states in m-dimensional materials, such as one-dimensional hinge states in three-dimensional materials and zero-dimensional corner states in two-dimensional materials.

Researchers at CIC nanoGUNE BRTA, Charles University in Prague and IKERBASQUE have designed a new complex material with unique properties that could be beneficial for spintronics.

Twist engineering has emerged as a fascinating approach for modulating electronic properties in van der Waals heterostructures. While theoretical works have predicted the modulation of spin texture in graphene-based heterostructures by twist angle, experimental studies are lacking. In this recent work, by performing spin precession experiments, the team demonstrates tunability of the spin texture and associated spin–charge interconversion with twist angle in WSe₂/graphene heterostructures.

Researchers use ultrashort laser pulses to trigger a spin-aligned electron flow on the few-femtosecond timescale—opening up a possible path toward faster spintronic devices.

Spintronics technology requires a rapid, controlled way to create spin currents. To that end, the researchers have demonstrated that short laser pulses can create spin currents within a few femtoseconds (10–15 s) — about 30 times faster than previous techniques. The method, they believe, should provide a more flexible and precise way to generate spin currents by taking advantage of the control that physicists have over laser light.

Researchers at King Abdullah University of Science and Technology (KAUST) and Khalifa University of Science and Technology have investigated the transmission, tunneling magnetoresistance ratio and spin injection efficiency of bilayer LaI₂ using a combination of first-principles calculations and the non-equilibrium Green’s function method. 

Multilayer graphene electrodes were used by the team, to build a magnetic tunnel junction with bilayer LaI₂ as ferromagnetic barrier. The magnetic tunnel junction reportedly proved to be a perfect spin filter device with an impressive tunneling magnetoresistance ratio of 653% under a bias of 0.1 V and a still excellent performance in a wide bias range. The team said that in combination with the obtained high spin injection efficiency, this could hold great potential from an application point of view.

Researchers from the University of California - Riverside, National Institute of Standards and Technology, Massachusetts Institute of Technology and Rigaku Americas have developed a new superconductor material that could potentially be used in quantum computing and be a candidate 'topological superconductor.'

A topological superconductor uses a delocalized state of an electron or hole (a hole behaves like an electron with positive charge) to carry quantum information and process data in a robust manner. The researchers reported in their recent work that they combined trigonal tellurium with a surface state superconductor generated at the surface of a thin film of gold. Trigonal tellurium is a chiral material, which means it cannot be superimposed on its mirror image, like our left and right hands. Trigonal tellurium is also non-magnetic. Nonetheless, the researchers observed quantum states at the interface that host well-defined spin polarization. The spin polarization allows the excitations to be potentially used for creating a spin quantum bit -- or qubit.

Researchers from ETH Zurich recently developed a method to control the quantum states of single electron spins using spin-polarized currents, which could enhance quantum computing technologies. The new technique offers more precise, localized control compared to traditional methods using electromagnetic fields, potentially improving the manipulation of quantum states in devices like qubits. 

Control over quantum systems is typically achieved by time-dependent electric or magnetic fields. Alternatively, electronic spins can be controlled by spin-polarized currents. In their recent work, the team demonstrated coherent driving of a single spin by a radiofrequency spin-polarized current injected from the tip of a scanning tunneling microscope into an organic molecule. With the excitation of electron paramagnetic resonance, the scientists established dynamic control of single spins by spin torque using a local electric current. In addition, their work highlights the dissipative action of the spin-transfer torque, in contrast to the nondissipative action of the magnetic field, which allows for the manipulation of individual spins based on controlled decoherence.

Researchers at India's Institute of Nano Science and Technology (INST), an autonomous research institution of Department of Science and Technology (DST), recently produced a transparent conducting interface between two insulating materials with room temperature spin polarized electron gas, which allows for see-through devices with efficient spin currents. 

Prof. Suvankar Chakraverty and his group at INST have produced a 2D Electron Gas (2DEG) with room temperature spin polarization at the interface composed of chemicals LaFeO₃ and SrTiO₃. They grew super lattices and hetero structures of oxide materials to realize new and exotic two-dimensional electron gas at the interface of two insulating oxides that could be useful for next generation quantum devices.

Researchers at the University of Tübingen, Helmholtz-Zentrum Berlin, University of Nebraska and Trinity College have used a very thin layer of radicals, 10000 times thinner than a human hair, to coat a ferromagnetic material, polycrystalline cobalt, to change the magnetic properties of cobalt at the junction with the radicals.

Purely organic radicals are a family of molecules composed only of light elements, such as carbon, nitrogen, and oxygen. They are transparent, light, and flexible materials. They promise lower costs of production and sustainable, and recyclable chemistry. These radicals are organic molecules that carry an unpaired electron, i.e., they are materials with permanent magnetic properties. They must be used as a film in a device, i.e., the radical molecules cover a substrate such as a metal surface, forming a coating.