1 Institute of Low Temperature and Structural Research, Polish Academy of Sciences, PL-50-950 Wroclaw, Poland 2 Department of Chemistry, University of Warsaw, Al. Zwirki i Wigury 101, PL-02-089 Warsaw, Poland 3 Department of Physics, Aoyama-Gakuin University, Tokyo, Japan 4 SUPRATECS, Montefiore Institute of Electricity B28, University of Liege, Sart Tilman, B-4000 Liege, Belgium 5 SUPRATECS, I...

Metal diborides are a class of ceramic materials with crystal structures consisting hexagonal sheets boron atoms alternating planes metal held together mixed character ionic/covalent bonds. Many the ultrahigh-temperature ceramics such as HfB2, TaB2, and ZrB2, which have melting points above 3000 °C, high mechanical hardness strength at temperatures, chemical resistance, while MgB2 is supercondu...

Precision measurements of the microwave surface resistance Rs of in situ MgB2 films directly reveal an exponential behavior of Rs at low temperature indicating a fully-gapped order parameter. The entire temperature dependence of Rs is well described by a Mattis–Bardeen formalism, but with a small gap ratio of D(0)/kTc50.72, corresponding to D(0)51.9 meV. © 2002 American Institute of Physics. @D...

The magnetic behavior of iron sheathed magnesium diboride (MgB2) wires was investigated. Global magnetization measurements have shown unusual critical current density variations compare to a superconductor with no magnetic environment. Local quantitative studies, through MO images, are linked to these global magnetization measurements in order to better understand the observed results. It is sh...