Phys.org May 1, 2023 Magnesium diboride (MgB2), a binary compound, behaves as a superconductor at a moderate temperature of around 39 K (-234°C). It can replace conventional low-temperature superconductors. However, it suffers from weak magnetic flux pinning. To enhance pinning, it is essential to tune the pinning centers in MgB2—the boundaries of grains or small crystals that constitute MgB2. An international team of researchers (Japan, Czech Republic) used high-energy ultra-sonication for refining coarse B powder dispersed in 2-propanol up to nanoscale sizes. Utrasonic vibrations imparted high speeds to B particles in the solvent, leading to collisions. The resulting friction and […]
Tag Archives: High temperature superconductivity
Leading the way in superconductor research: New compounds of lanthanum and hydrogen
Phys.org November 22, 2022 An international team of researchers (Germany, UK, Sweden, USA – University of Chicago) has presented the results of their single-crystal X-ray diffraction studies on lanthanum hydrides which revealed an unexpected chemical and structural diversity of lanthanum hydrides synthesized in the range of 50 to 180 GPa. They produced seven lanthanum hydrides LaH3, LaH~4, LaH4+δ, La4H23, LaH6+δ, LaH9+δ, and LaH10+δ, and determined the atomic coordinates of lanthanum in their structures. The regularities in rare-earth element hydrides the team has shown provide clues to guide the search for other synthesizable hydrides and candidate high-temperature superconductors. The hydrogen content variability […]
Exploring the bounds of room-temperature superconductivity
Science Daily March 9, 2022 Several reports of high superconducting transition temperature (Tc) up to 287 K in hydrides under pressure of up to 267 GPa have appeared. The ultrahigh pressure needed to create the high-temperature superconductivity (HTS) in hydrides has hampered the detailed study of the high-pressure-induced high-Tc superconductivity state, as well as any potential applications. Researchers at the University of Houston developed a pressure-quench process (PQP) and demonstrated it successfully in stabilizing at ambient the high-pressure-induced superconducting phases and other phases in the non-superconducting element Sb, the binary superconducting compound FeSe, and the non-superconducting compound Cu-doped FeSe. According […]
Study raises new possibilities for triggering room-temperature superconductivity with light
Phys.org February 9, 2022 An international team of researchers (South Korea, USA – SLAC National Accelerator Laboratory, Germany, Japan) explored a photoinduced normal state of YBCO through a charge density wave (CDW) with time-resolved resonant soft x-ray scattering, as well as a high magnetic field x-ray scattering. In the nonequilibrium state where people predict a quenched superconducting state based on the previous optical spectroscopies, they experimentally observed a similar analogy to the competition between superconductivity and CDW shown in the equilibrium state. Their results provide a critical clue that the characteristics of the photoinduced normal state show a solid resemblance […]
The pressure is off and high temperature superconductivity remains
Phys.org July 8, 2021 The grand challenge in superconductivity research and development is no longer restricted to further increasing the superconducting transition temperature under extreme conditions and must now include concentrated efforts to lower, and better yet remove, the applied pressure required. An international team of researchers (USA – Houston University, Rice University, China) has shown such a possibility in the pure and doped high-temperature superconductor FeSe by retaining, at ambient pressure via pressure quenching, its Tc up to 37 K and other pressure-induced phases. They observed that some phases remain stable without pressure at up to 300 K and […]
Researchers synthesize ‘impossible’ superconductor
Phys.org October 1, 2019 The superconductors known today can only work at very low temperatures and extremely high pressures. As an alternative to metallizing hydrogen, an international team of researchers (China, USA – SUNY Stony Brook) placed a microscopic sample of the metal cerium into a diamond anvil cell, along with a chemical that releases hydrogen and heated with a laser. The cerium sample was squeezed between two flat diamonds to enable the pressure needed for the reaction. As the pressure grew, cerium hydrides with a progressively larger proportion of hydrogen formed in the reactor – CeH2, CeH3, etc. Through […]
Scientists finally find superconductivity in place they have been looking for decades
Phys.org September 26, 2019 The biggest obstacle to making superconductors operate at higher temperatures and making superconductivity more robust has been the lack of a model. High-temperature superconductors are quantum materials, where electrons cooperate to produce unexpected properties. A team of researchers in the US (Stanford University, SLAC National Accelerator Laboratory) created a virtual version of a cuprate on a square lattice, like a wire fence with square holes where each virtual atom can accommodate at most two electrons that are free to jump or hop—either to their immediate neighbors on the square lattice or diagonally across each square. When […]
Graphene on the way to superconductivity
Science Daily November 9, 2018 Previously researchers at MIT showed that it is possible to generate a form of superconductivity in a system of two layers of graphene under very specific conditions using a complex method. Researchers in Germany have developed a simpler technique by heating silicon carbide crystal until silicon atoms evaporate from the surface, leaving first a single-layer of graphene on the surface, and then a second layer of graphene. The two graphene layers are not twisted against each other but lie exactly on top of each other. They argue that their two-dimensional flat band model and the […]