Superconductivity Observed in Tantalum Polyhydride at High Pressure

We report experimental discovery of tantalum polyhydride superconductor.It was synthesized under highpressure and high-temperature conditions using diamond anvil cell combined with in situ high-pressure laser heating techniques.The superconductivity was investigated via resistance measurements at pressures.The highest superconducting transition temperature T_(c)was found to be~30 K at 197 GPa in the sample that was synthesized at the same pressure with~2000 K heating.The transitions are shifted to low temperature upon applying magnetic fields that support the superconductivity nature.The upper critical field at zero temperatureμ_0H_(c2)(0)of the superconducting phase is estimated to be~20 T that corresponds to Ginzburg-Landau coherent length~40 A.Our results suggest that the superconductivity may arise from 143d phase of TaH_(3).It is,for the first time to our best knowledge,experimental realization of superconducting hydrides for the VB group of transition metals.