Abstract:

Since the recent discovery of Akimitsu [1] of superconductivity in MgB2 at 39 K, MB2 materials (M = Transition Metal) with the same prototype structure as MgB2 are considered as candidates for multiband superconductivity. This discovered motivated the investigation to search for superconductivity in similar systems. Binary diborides can crystallize in different structure types, although the great majority are those presenting the AlB2-type structure (P6/mmm space group, number 191) [2]. Although many compounds of MB2 can crystallize in the AlB2 type structure, superconductivity in this class of material is relatively rare. For example, the ZrB2 which crystallizes in the AlB2 prototype structure, does not presents superconductivity. Recently we showed that small V doping at Zr site in ZrB2 leads to superconductivity [4]. In this work, we present structural, micro structural, electrical and magnetic studies on Zr1-xNbxB2, with 0 ≤ x ≤ 0.5.Polycrystalline samples of Zr1-xNbxB2 were prepared by arc-melting. The X-ray diffraction patterns were analyzed by Rietveld refinement, allowing the identification of single-phased compounds. The materials were characterized by Scanning Electronic Microscopy (SEM). The SEM micrographs with EDS analysis showed that the presents a uniform composition. Specific heat, magnetization and resistivity measurements confirmed that all prepared samples were superconducting.