A new layered Ti-based pnictide oxide superconductor, Ba 1-xNa xTi 2Sb 2O (0.0 ≥ x ≥ 0.33), is reported. X-ray studies revealed that it crystallizes in the tetragonal CeCr 2Si 2C structure. The undoped parent compound, BaTi 2Sb 2O [P4/mmm; a = 4.1196(1) Å; c = 8.0951(2) Å], exhibits a charge density wave (CDW)/spin density wave (SDW) transition at 54 K. Upon chemical doping with Na, the CDW/SDW transition is systematically suppressed, and superconductivity arises with the critical temperature (T c) increasing to 5.5 K. Bulk superconductivity was confirmed by resistivity, magnetic, and heat capacity measurements. Like the high-T c cuprates and the iron pnictides, the superconductivity in BaTi 2Sb 2O arises from an ordered state. Similarities and differences between BaTi 2Sb 2O and the cuprate and iron pnictide superconductors are discussed.
All Science Journal Classification (ASJC) codes
- 化學 (全部)