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The electrical properties of polycrystalline SrSi2 were examined by electrical resistivity measurements at temperatures ranging from 2 to 760 K and Hall coefficient measurements at temperatures ranging from 10 to 300 K. These measurements revealed that SrSi2 is a narrow-gap semiconductor with an energy gap of 0.035 eV whose dominant carriers are holes. [ABSTRACT FROM AUTHOR]

The electrical properties of polycrystalline SrSi2 were examined by electrical resistivity measurements at temperatures ranging from 2 to 760 K and Hall coefficient measurements at temperatures ranging from 10 to 300 K. These measurements revealed that SrSi2 is a narrow-gap semiconductor with an energy gap of 0.035 eV whose dominant carriers are holes. [ABSTRACT FROM AUTHOR]

Superconducting MgB2 films have been fabricated on stainless steel substrates by means of electroplating in a molten electrolyte composed of MgCl2, MgB2O4, NaCl, and KCl containing a fractional amount of CuCl2. Microscopic observation has revealed that the electroplated films and substrates are combined with each other through Cu-rich layers at the interfaces. Transport measurements have shown that the electroplated MgB2 films possess an upper critical field, Hc2(0), of 28 T, an irreversibility field, Hirr(0), of 13 T, and a critical current density, Jc(5 K,0 T), of 25 000 A/cm2, which suggests that the electroplating in molten salts is a promising alternative to the powder-in-tube method for the fabrication of MgB2 tapes. [ABSTRACT FROM AUTHOR]

Optical and electrical properties of polycrystalline orthorhombic BaSi[sub 2] prepared by arc melting in Ar atmosphere were investigated. The optical absorption spectra measured at room temperature showed that indirect and direct absorption edges were 1.15 and 1.25 eV, respectively. The activation energy estimated from temperature dependence of the resistivity was 1.10 eV. These results agreed well with a calculated band structure of the orthorhombic BaSi[sub 2] by first principles calculation using density functional theory. [ABSTRACT FROM AUTHOR]

A ternary silicide Ca(Al[sub 0.5],Si[sub 0.5])[sub 2] was prepared by Ar arc melting. Powder x-ray diffraction measurement indicates that it has the AlB[sub 2]-type structure with lattice constants of a=4.1905(5) and c=4.3992(8) Å, where Si and Al atoms are arranged in the disordered honeycomb lattice and Ca atoms are intercalated between them. The silicide is isostructural with a superconductor MgB[sub 2]. Electrical resistivity and dc magnetization measurements revealed that it is a superconductor with a T[sub C] of 7.7 K. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]