3 research outputs found
Large Exchange Bias, High Dielectric Constant, and Outstanding Ionic Conductivity in a SingleâPhase Spin Glass
Large Exchange Bias, High Dielectric Constant, and Outstanding Ionic Conductivity in a SingleâPhase Spin Glass
The multigram synthesis of K2[Fe3S4] starting from K2S and FeS is presented, and its electronic and magnetic properties are investigated. The title compound obtains a defect variant of the K[Fe2Se2] structure type. Dielectric and impedance measurements indicate a dielectric constant of 1120 at 1 kHz and an outstanding ionic conductivity of 24.37 mS cmâ1 at 295 K, which is in the range of the highest reported value for potential solidâstate electrolytes for potassiumâion batteries. The Seebeck coefficient of the nâtype conductor amounts to â60 ”V Kâ1 at 973 K. The mismatch of the measured electrical resistivity and the predicted metalâlike band structure by periodic quantum chemical calculations indicates Mott insulating behavior. Magnetometry demonstrates temperatureâdependent, large exchange bias fields of 35 mT, as a consequence of the coexistence of spin glass and antiferromagnetic orderings due to the iron vacancies in the lattice. In addition, the decreasing training effects of 34% in the exchange bias are identified at temperatures lower than 20 K. These results demonstrate the critical role of iron vacancies in tuning the electronic and magnetic properties and a multifunctional material from abundant and accessible elements
3D-printed equipment to decouple (powder) X-ray diffraction sample preparation and measurement
An alternative storage method to separate sample preparation from single-crystal and powder X-ray diffraction measurements at home source diffractometers is described. For single crystals, a setup is presented which allows storage of preselected crystals under cryogenic and ambient temperatures. For powders, a disposable sample holder is introduced. The method is suitable for the storage of air- and moisture-sensitive samples. Equipment made of biodegradable polylactic acid is produced by 3D printing and can be adapted to individual needs. As 3D printers are widely available at research institutions nowadays, models of the presented equipment are provided for the reader to allow easy reproduction