Superconductivity in Zr1-xVxB2

Since the discovery of superconductivity in MgB$_{2}$, much attention has been give for research in new diboride with potential for exhibit superconductivity. There are many diboride of refractory metals which crystallize in the same prototype structure than MgB$_{2}$ (AlB$_{2}$ prototype structure). However, only NbB$_{2}$ can exhibit superconductivity with superconductor critical temperature close to 3.5 K on the optimum composition. Some authors have been reported superconductivity in ZrB$_{2}$ with critical temperature close to 5.5 K, but this result was not reproduced for other research groups. In this work we present results which show that small substitution of Zr by V in the Zr$_{1-}$xVxB$_{2}$ is able for induce superconductivity in the matrix phase (ZrB$_{2}$). The best composition gives a superconducting critical temperature close to 8.5 K.