Synthesis and characterization of a new superconductor Nb1−xMgxB2

Synthesis, lattice parameter changes, grain morphology, superconductivity and specific heat of a new superconductor Nb(1-x)Mg(x)B(2) (0.0 <= x <= 0.40) series were reported. Magnetization and resistance measurements indicate that the superconducting transition temperature T(C) of Nb(1-x)Mg(x)B(2) with x = 0.10-0.40 is similar to 5 K. A large Meissner signal and the result of specific heat measurements indicate that the superconductors have a bulk superconductivity. The Debye temperature theta(D) determined by the measurement of specific heat is 419(+/- 10) K for Nb(0.75)Mg(0.25)B(2).