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We report the first study on the significant effect of in-situ hydrostatic pressure on the magnetic relaxation in Fe1−xCoxSe0.5Te0.5 single crystals. We find that vortex creep rates are significantly suppressed by pressure, and a crossover from elastic to plastic creep is observed. The pressure also induces vortex creep to move from the large bundle to the small bundle region. Our study indicates that in-situ hydrostatic pressure is very effective for not only significantly increasing the pinning energy and the critical current density, but also reducing the size of flux bundles to suppress the decrease in current density from vortex motion.

Cl-doped Fe(Se, Te)superconductors were fabricated through a melting method followed by hydrostatic pressure (HP)post treatment. A dual coordination effect has been aroused, viz. the introduction of Cl − ions triggered the nucleation and growth of nanometric point-like secondary phase as extra pinning centers, while HP strengthened the pinning competence of these point defects. As a result, the superconducting phase volume, critical temperature, and critical current density have been improved by 12.2%, 42.3%, and nearly 100 times, respectively, compared with the undoped sample without HP.

We report the first study on the significant effect of in-situ hydrostatic pressure on the magnetic relaxation in Fe1−xCoxSe0.5Te0.5 single crystals. We find that vortex creep rates are significantly suppressed by pressure, and a crossover from elastic to plastic creep is observed. The pressure also induces vortex creep to move from the large bundle to the small bundle region. Our study indicates that in-situ hydrostatic pressure is very effective for not only significantly increasing the pinning energy and the critical current density, but also reducing the size of flux bundles to suppress the decrease in current density from vortex motion.

Cl-doped Fe(Se, Te)superconductors were fabricated through a melting method followed by hydrostatic pressure (HP)post treatment. A dual coordination effect has been aroused, viz. the introduction of Cl − ions triggered the nucleation and growth of nanometric point-like secondary phase as extra pinning centers, while HP strengthened the pinning competence of these point defects. As a result, the superconducting phase volume, critical temperature, and critical current density have been improved by 12.2%, 42.3%, and nearly 100 times, respectively, compared with the undoped sample without HP.

We report the first study on the significant effect of in-situ hydrostatic pressure on the magnetic relaxation in Fe1−xCoxSe0.5Te0.5 single crystals. We find that vortex creep rates are significantly suppressed by pressure, and a crossover from elastic to plastic creep is observed. The pressure also induces vortex creep to move from the large bundle to the small bundle region. Our study indicates that in-situ hydrostatic pressure is very effective for not only significantly increasing the pinning energy and the critical current density, but also reducing the size of flux bundles to suppress the decrease in current density from vortex motion.

Cl-doped Fe(Se, Te)superconductors were fabricated through a melting method followed by hydrostatic pressure (HP)post treatment. A dual coordination effect has been aroused, viz. the introduction of Cl − ions triggered the nucleation and growth of nanometric point-like secondary phase as extra pinning centers, while HP strengthened the pinning competence of these point defects. As a result, the superconducting phase volume, critical temperature, and critical current density have been improved by 12.2%, 42.3%, and nearly 100 times, respectively, compared with the undoped sample without HP.

Cl-doped Fe(Se, Te)superconductors were fabricated through a melting method followed by hydrostatic pressure (HP)post treatment. A dual coordination effect has been aroused, viz. the introduction of Cl − ions triggered the nucleation and growth of nanometric point-like secondary phase as extra pinning centers, while HP strengthened the pinning competence of these point defects. As a result, the superconducting phase volume, critical temperature, and critical current density have been improved by 12.2%, 42.3%, and nearly 100 times, respectively, compared with the undoped sample without HP.

We report the first study on the significant effect of in-situ hydrostatic pressure on the magnetic relaxation in Fe1−xCoxSe0.5Te0.5 single crystals. We find that vortex creep rates are significantly suppressed by pressure, and a crossover from elastic to plastic creep is observed. The pressure also induces vortex creep to move from the large bundle to the small bundle region. Our study indicates that in-situ hydrostatic pressure is very effective for not only significantly increasing the pinning energy and the critical current density, but also reducing the size of flux bundles to suppress the decrease in current density from vortex motion.

Cl-doped Fe(Se, Te)superconductors were fabricated through a melting method followed by hydrostatic pressure (HP)post treatment. A dual coordination effect has been aroused, viz. the introduction of Cl − ions triggered the nucleation and growth of nanometric point-like secondary phase as extra pinning centers, while HP strengthened the pinning competence of these point defects. As a result, the superconducting phase volume, critical temperature, and critical current density have been improved by 12.2%, 42.3%, and nearly 100 times, respectively, compared with the undoped sample without HP.

We report the first study on the significant effect of in-situ hydrostatic pressure on the magnetic relaxation in Fe1−xCoxSe0.5Te0.5 single crystals. We find that vortex creep rates are significantly suppressed by pressure, and a crossover from elastic to plastic creep is observed. The pressure also induces vortex creep to move from the large bundle to the small bundle region. Our study indicates that in-situ hydrostatic pressure is very effective for not only significantly increasing the pinning energy and the critical current density, but also reducing the size of flux bundles to suppress the decrease in current density from vortex motion.

A thermoelectric material consisting of Cu2Se incorporated with up to 0.45 wt% of graphene nanoplates is reported. The carbon-reinforced Cu2Se exhibits an ultra-high thermoelectric figure-of-merit of zT = 2.44 ± 0.25 at 870 K. Microstructural characterization reveals dense, nanostructured grains of Cu2Se with multilayer-graphene and graphite agglomerations located at grain boundaries. High temperature X-ray diffraction shows that the graphene incorporated Cu2Se matrix retains a cubic structure and the composite microstructure is chemically stable. Based on the experimental structure, density functional theory was used to calculate the formation energy of carbon point defects and the associated phonon density of states. The isolated carbon inclusion is shown to have a high formation energy in Cu2Se whereas graphene and graphite phases are enthalpically stable relative to the solid solution. Neutron spectroscopy proves that there is a frequency mismatch in the phonon density of states between the carbon honeycomb phases and cubic Cu2Se. This provides a mechanism for the strong scattering of phonons at the composite interfaces, which significantly impedes the conduction of heat and enhances thermoelectric performance.

A thermoelectric material consisting of Cu2Se incorporated with up to 0.45 wt% of graphene nanoplates is reported. The carbon-reinforced Cu2Se exhibits an ultra-high thermoelectric figure-of-merit of zT = 2.44 ± 0.25 at 870 K. Microstructural characterization reveals dense, nanostructured grains of Cu2Se with multilayer-graphene and graphite agglomerations located at grain boundaries. High temperature X-ray diffraction shows that the graphene incorporated Cu2Se matrix retains a cubic structure and the composite microstructure is chemically stable. Based on the experimental structure, density functional theory was used to calculate the formation energy of carbon point defects and the associated phonon density of states. The isolated carbon inclusion is shown to have a high formation energy in Cu2Se whereas graphene and graphite phases are enthalpically stable relative to the solid solution. Neutron spectroscopy proves that there is a frequency mismatch in the phonon density of states between the carbon honeycomb phases and cubic Cu2Se. This provides a mechanism for the strong scattering of phonons at the composite interfaces, which significantly impedes the conduction of heat and enhances thermoelectric performance.

A thermoelectric material consisting of Cu2Se incorporated with up to 0.45 wt% of graphene nanoplates is reported. The carbon-reinforced Cu2Se exhibits an ultra-high thermoelectric figure-of-merit of zT = 2.44 ± 0.25 at 870 K. Microstructural characterization reveals dense, nanostructured grains of Cu2Se with multilayer-graphene and graphite agglomerations located at grain boundaries. High temperature X-ray diffraction shows that the graphene incorporated Cu2Se matrix retains a cubic structure and the composite microstructure is chemically stable. Based on the experimental structure, density functional theory was used to calculate the formation energy of carbon point defects and the associated phonon density of states. The isolated carbon inclusion is shown to have a high formation energy in Cu2Se whereas graphene and graphite phases are enthalpically stable relative to the solid solution. Neutron spectroscopy proves that there is a frequency mismatch in the phonon density of states between the carbon honeycomb phases and cubic Cu2Se. This provides a mechanism for the strong scattering of phonons at the composite interfaces, which significantly impedes the conduction of heat and enhances thermoelectric performance.

A thermoelectric material consisting of Cu2Se incorporated with up to 0.45 wt% of graphene nanoplates is reported. The carbon-reinforced Cu2Se exhibits an ultra-high thermoelectric figure-of-merit of zT = 2.44 ± 0.25 at 870 K. Microstructural characterization reveals dense, nanostructured grains of Cu2Se with multilayer-graphene and graphite agglomerations located at grain boundaries. High temperature X-ray diffraction shows that the graphene incorporated Cu2Se matrix retains a cubic structure and the composite microstructure is chemically stable. Based on the experimental structure, density functional theory was used to calculate the formation energy of carbon point defects and the associated phonon density of states. The isolated carbon inclusion is shown to have a high formation energy in Cu2Se whereas graphene and graphite phases are enthalpically stable relative to the solid solution. Neutron spectroscopy proves that there is a frequency mismatch in the phonon density of states between the carbon honeycomb phases and cubic Cu2Se. This provides a mechanism for the strong scattering of phonons at the composite interfaces, which significantly impedes the conduction of heat and enhances thermoelectric performance.

A thermoelectric material consisting of Cu2Se incorporated with up to 0.45 wt% of graphene nanoplates is reported. The carbon-reinforced Cu2Se exhibits an ultra-high thermoelectric figure-of-merit of zT = 2.44 ± 0.25 at 870 K. Microstructural characterization reveals dense, nanostructured grains of Cu2Se with multilayer-graphene and graphite agglomerations located at grain boundaries. High temperature X-ray diffraction shows that the graphene incorporated Cu2Se matrix retains a cubic structure and the composite microstructure is chemically stable. Based on the experimental structure, density functional theory was used to calculate the formation energy of carbon point defects and the associated phonon density of states. The isolated carbon inclusion is shown to have a high formation energy in Cu2Se whereas graphene and graphite phases are enthalpically stable relative to the solid solution. Neutron spectroscopy proves that there is a frequency mismatch in the phonon density of states between the carbon honeycomb phases and cubic Cu2Se. This provides a mechanism for the strong scattering of phonons at the composite interfaces, which significantly impedes the conduction of heat and enhances thermoelectric performance.