A new information storage and processing device

Phys.org  July 29, 2021 An international team of researchers (USA – New York University, UC San Diego, France) combined the unique properties of quantum materials together with that of spintronic magnetic devices. They presented spin torque ferromagnetic resonance characteristics of a hybrid metal-insulator-transition oxide/ ferromagnetic metal nano constriction. Their samples incorporate vanadium trioxide (V2O3), with Ni, Permalloy (Ni80Fe20) and platinum layers patterned into a nano constriction geometry. The first order phase transition in V2O3 is shown to lead to systematic changes in the resonance response and hysteretic current control of the ferromagnetic resonance frequency. The output signal can be systematically […]

Future information technologies: Topological materials for ultrafast spintronics

Phys.org  July 16, 2021 To understand how fast excited electrons in the bulk and on the surface of Sb react to the external energy input, and to explore the mechanisms governing their response an international team of researchers (Germany, Russia, Ireland) used time-, spin- and angle-resolved photoemission to femtosecond-laser excitation. The data showed a ‘kink’ structure in transiently occupied energy-momentum dispersion of surface states, which can be interpreted as an increase in effective electron mass. They were able to show that this mass enhancement plays a decisive role in determining the complex interplay in the dynamical behaviors of electrons from […]

Quantum sensing: Odd angles make for strong spin-spin coupling

Science Daily  May 25, 2021 Exotic quantum vacuum phenomena are predicted in cavity quantum electrodynamics systems with ultra-strong light-matter interactions. However, such predictions have not been realized because antiresonant interactions are typically negligible compared to resonant interactions in light-matter systems. An international team of researchers (USA – Rice University, Japan, Germany, China) reports an unusual, ultra-strongly coupled matter-matter system of magnons that is analytically described by a unique Hamiltonian in which the relative importance of resonant and antiresonant interactions can be easily tuned and the latter can be made vastly dominant. They found a regime where vacuum Bloch-Siegert shifts, the […]

Concept for a new storage medium

EurekAlert  February 22, 2021 The control and understanding of antiferromagnetic domain walls are key ingredients for advancing antiferromagnetic spintronic technologies. However, studies of the intrinsic mechanics of individual antiferromagnetic domain walls are difficult because they require sufficiently pure materials and suitable experimental approaches to address domain walls on the nanoscale. An international team of researchers (Switzerland, Germany, Ukraine) nucleated isolated 180° domain walls in a single crystal of Cr2O3, a prototypical collinear magnetoelectric antiferromagnet. They studied their interaction with topographic features fabricated on the sample. They demonstrated domain wall manipulation through the resulting engineered energy landscape and showed that the […]

Old silicon learns new tricks

Science Daily  January 6, 2021 Using a combination of standard dry etching and chemical etching an international team of researchers (Japan, China) fabricated arrays of pyramid-shaped silicon nanostructures. An ultrathin layer of iron was deposited onto the silicon to impart unusual magnetic properties. The pyramids’ atomic-level orientation defined the orientation and thus the properties-of the overlaying iron. Epitaxial growth of iron enabled shape anisotropy of the nanofilm. The curve for the magnetization as a function of the magnetic field was rectangular-like shaped but with breaking points which were caused by asymmetric motion of magnetic vortex bound in pyramid apex. They […]

An unusual superconductor

Phys.org  September 3, 2020 Researchers in China investigated the superconducting properties of two-dimensional crystalline superconducting PdTe2 films grown by molecular beam epitaxy. They observed the experimental evidence of anomalous metallic state and detected type-II Ising superconductivity existing in centrosymmetric systems. Moreover, the superconductivity of PdTe2 films remains almost the same for more than 20 months without any protection layer. This macro-size ambient-stable superconducting system with strong spin-orbit coupling shows great potentials in superconducting electronic and spintronic applications…read more.

In leap for quantum computing, silicon quantum bits establish a long-distance relationship

EurekAlert  December 25, 2019 Silicon spin qubits have several advantages over superconducting qubits – they retain their quantum state longer than competing qubit technologies and they could be manufactured at low cost. A team of researchers in the US (Princeton University, industry) connected the qubits via a “wire” which is a narrow cavity containing a photon that picks up the message from one qubit and transmits it to the next qubit. The two qubits were located about half a centimeter apart. The team succeeded in tuning both qubits independently of each other while still coupling them to the photon. An […]

Scientists discover first antiferromagnetic topological quantum material

Science Daily  December 19, 2019 An international team of researchers led by Spain has developed a crystal growing technique for intrinsically magnetic topological material manganese-bismuth telluride (MnBi2Te4) and characterized the physical properties of the crystals. The team was able to prove both in theory and in spectroscopic experiments that MnBi2Te4 is the first antiferromagnetic topological insulator (AFMTI) below its Néel temperature. They optimized the synthesis protocol for the new material so that MnBi2Te4 single crystals can be produced more easily. Recent findings show that there are even more structural derivatives of MnBi2Te4, which are relevant in the context of MTI…read […]

New spin directions in pyrite an encouraging sign for future spintronics

Science Daily  November 12, 2019 Generating and manipulating out-of-plane spins without applying an external electric or magnetic field has been a key challenge in spintronics. Researchers in Australia demonstrate for the first time that pyrite-type (Pyrite is an iron-sulfide mineral that displays multiple internal planes of electronic symmetry) crystals can host unconventional energy- and direction-dependent spin textures on the surface, with both in-plane and out-of-plane spin components, in sharp contrast to spin textures in conventional topological materials. The findings provide a platform for experimentalists to detect and exploit unconventional surface spin textures in future spin-based nanoelectronic devices…read more. Open Access […]

Conductivity at the edges of graphene bilayers

EurekAlert  September 11, 2019 At the edges of graphene bilayers atoms can exist in a quantum spin Hall state (QSH) depending on spin-orbit coupling (SOC). While the QSH state is allowed for ‘intrinsic’ SOC, it is destroyed by ‘Rashba’ SOC. Researchers in India have shown that the interaction between the two types of SOC are responsible for variations in the ways in which graphene bilayers conduct electricity. For nanoribbons of bilayer graphene, whose edge atoms are arranged in zigzag patterns, the bands of electron energies which are allowed and forbidden are significantly different to those found in monolayer graphene. This […]