Category Physics

Single nanocrystal spectroscopy identifies the interaction between zero-dimensional CdSe/ZnS nano crystals (quantum dots) and two-dimensional layered tin disulfide as a non-radiative energy transfer, whose strength increases with increasing number of tin disulfide layers. Such hybrid materials could be used in optoelectronic devices such as photovoltaic solar cells, light sensors, and LEDs. Credit: Brookhaven National Laboratory

It paves the way for better optoelectronic apps eg energy-harvesting photovoltaics, light sensors, LEDs. Scientists combined excellent light-harvesting properties of quantum dots with the tunable electrical conductivity of a layered tin disulfide semiconductor...

Magnetic order in (Sr,Na)Fe2As2: The crystal structure contains planes of iron atoms (shown as red spheres). Half the iron sites have a magnetization (shown as red arrows), which points either up or down, but the other half have zero magnetization. This shows that the magnetism results from the constructive and destructive interference of two magnetization waves, a clear sign that the magnetic electrons are itinerant, which means they are not confined to a single site. The same electrons are responsible for the superconductivity at lower temperature. Credit: Image courtesy of DOE/Argonne National Laboratory

Scientists have discovered only half the atoms in some iron-based superconductors are magnetic, providing the first conclusive demonstration of the wave-like properties of metallic magn...

This image of a magnet levitated over a high-temperature superconductor array shows rectangular TFMs (black) levitating a heavy ferromagnet (silver) above a container of liquid nitrogen. Credit: Weinstein/University of Houston

Uni of Houston physicists report finding major theoretical flaws in the generally accepted understanding of how a superconductor traps and holds a magnetic field. More than 50 years ago, C.P. Bean, a scientist at GE, developed a theoretical explanation known as the “Bean Model” or “Critical State Model.” The basic property of superconductors is they represent 0 “resistance” to electrical circuits. Superconductors consume 0 energy and can store it for a long period of time. Those that store magnetic energy ie “trapped field magnets” or TFMs – can behave like a magnet.

A High-Luminosity LHC coil similar to those incorporated into the successful magnet prototype shows the collaboration between CERN and the LHC Accelerator Research Program, LARP. Credit: Reidar Hahn, Fermilab

Engineers will incorporate more than 20 magnets similar to this model into the next iteration of the LHC, which will take the stage in 2026 and increase LHC’s luminosity by a factor of ten. That translates into a 10X increase in the data rate. “Building this magnet prototype was truly an international effort,” says Lucio Rossi, the head of the High-Luminosity (HighLumi) LHC project at CERN. “Half the magnetic coils inside the prototype were produced at CERN, and half at laboratories in the United States.”

During the original construction of the Large Hadron Collider, US Department of ...