Vacancies Engineering in Molybdenum Boride MBene Nanosheets to Activate Room-Temperature Ferromagnetism.

The rapid development of low energy dissipation spintronic devices has stimulated the search for air-stable 2D nanomaterials possessing room-temperature ferromagnetism. Here the experimental realization of 2D MoB nanosheets is reported with intrinsic room-temperature ferromagnetic characteristics by vacancy engineering. These nanosheets are synthesized by etching the bulk MAB phase (MoY)AlB into MoB nanosheets in ZnCl molten salt.

Low field controllable continuous spin switching in the thulium-ytterbium single crystal.

We report the spin reorientation transition (SRT) and the low field controllable continuous spin switching (SSW) of the TmYbFeO (TYFO) single crystal in this study. The SRT, characterized by the transition from (, , )-(, , ), occurs within the temperature range of 20-27 K. Under an external magnetic field of 50 Oe, the SSW occurs along the -axis at approximately 98 K due to the reversal of Tm magnetic moment induced by the magnetic coupling change between Tm and Fe, transitioning from a parallel to an antiparallel alignment.

Site-Selective Assembly of Centimeter-Scale Arrays of Precisely Oriented Magnetic Nanoellipsoids.

The precise organization and orientation of anisotropic nanoparticles (NPs) on substrates over a large area is key to the application of NP assemblies in functional optical, electronic, and magnetic devices, but achieving such high-precision NP assembly still remains challenging. Here, we demonstrate the site-selective assembly of magnetic nanoellipsoids into large-area precisely positioned, orientationally controlled arrays via a combination of chemical patterning and magnetic manipulation. Magnetic ellipsoidal NPs are selectively positioned on predetermined chemical patterns with high fidelity through electrostatic interactions and aligned uniformly in line with an applied magnetic field.

Tunable Noninteger Flux Quantum of Vortices in Superconducting Strips.

Flux quantization has been widely regarded as the hallmark of the macroscopic quantum state of superconductivity. However, practical design of superconductor devices exploiting finite size confinement effects may induce exotic phenomena, including nonquantized vortices. In our research, the magnetic flux of vortices has been studied in a series of superconducting strips as a function of the strip width and the penetration depth.

Low field control of spin switching and continuous magnetic transition in an ErFeO single crystal.

The magnetic behavior of a rare-earth orthoferrite ErFeO single crystal can be controlled by low magnetic fields from a few to hundreds of Oe. Here we investigated a high-quality ErFeO single crystal in the temperature range of 5-120 K, with two types of spin switching in the field-cooled-cooling (FCC) and field-cooled-warming (FCW) processes below the temperature of the spin reorientation (SR) transition from Γ to Γ at 98-88 K. The magnitude of the applied magnetic fields can regulate two types of spin switching along the -axis of the ErFeO single crystal but does not affect the type and temperature range of the SR transition.

Evolution of Superconducting Properties in FeSeTe Films Before and After Structure Avalanche.

By preparing a series of high-quality FeSeTe films on the CaF substrate via pulsed laser deposition, we reveal the evolution of the structure as well as the superconductivity with the film thickness. We have found that there exists a threshold thickness above which the critical temperature reaches its optimal value of 23.18 K with large activation energy, promising for high-field technological applications.

Emergence of exchange bias field in FeS superconductor with cobalt-doping.

Among all the iron-based superconductors, the 11 series has the simplest layered structure but exhibits rich physical phenomenon. In this work, we have synthesized FeCoS single crystals with tetragonal structure and studied their structure and magnetic properties. Magnetic susceptibility measurements indicate that the cobalt doping would suppress superconductivity and even introduce weak ferromagnetism besides antiferromagnetism.

Spin-orbit coupling in magnetoelectric Ba(ZnCo)FeO hexaferrites.

The Z-type hexaferrites Ba3(Zn1-xCox)2Fe24O41 (x = 0.2, 0.4, 0.

Direct Observation of Nanoscale Light Confinement without Metal.

Manipulation of light below the diffraction limit forms the basis of nanophotonics. Metals can confine light at the subwavelength scale but suffer from high loss of energy. Recent reports have theoretically demonstrated the possibility of light confinement below the diffraction limit using transparent dielectric metamaterials.

Tunable and switchable magnetic dipole patterns in nanostructured superconductors.

Design and manipulation of magnetic moment arrays have been at the focus of studying the interesting cooperative physical phenomena in various magnetic systems. However, long-range ordered magnetic moments are rather difficult to achieve due to the excited states arising from the relatively weak exchange interactions between the localized moments. Here, using a nanostructured superconductor, we investigate a perfectly ordered magnetic dipole pattern with the magnetic poles having the same distribution as the magnetic charges in an artificial spin ice.

Controlled Generation of Quantized Vortex-Antivortex Pairs in a Superconducting Condensate.

Quantized vortices, as topological defects, play an important role in both physics and technological applications of superconductors. Normally, the nucleation of vortices requires the presence of a high magnetic field or current density, which allow the vortices to enter from the sample boundaries. At the same time, the controllable generation of individual vortices inside a superconductor is still challenging.

Nanoscale assembly of superconducting vortices with scanning tunnelling microscope tip.

Vortices play a crucial role in determining the properties of superconductors as well as their applications. Therefore, characterization and manipulation of vortices, especially at the single-vortex level, is of great importance. Among many techniques to study single vortices, scanning tunnelling microscopy (STM) stands out as a powerful tool, due to its ability to detect the local electronic states and high spatial resolution.

Bound vortex dipoles generated at pinning centres by Meissner current.

One of the phenomena that make superconductors unique materials is the Meissner-Ochsenfeld effect. This effect results in a state in which an applied magnetic field is expelled from the bulk of the material because of the circulation near its surface of resistance-free currents, also known as Meissner currents. Notwithstanding the intense research on the Meissner state, local fields due to the interaction of Meissner currents with pinning centres have not received much attention.