Growth and superconductivity of 2H - Ni0.02TaSe2 single crystals

2H-Ni0.02TaSe2 single crystals were successfully grown via the iodine vapor transport technique. The typical dimension of the crystal is about 3×2×0.5 mm3. Compared with the parent compound 2H-TaSe2 with a superconducting transition temperature T C = 0.14  K, the electronic transport, specific-heat and magnetization results indicate that the superconductivity of the Ni0.02TaSe2 single crystal is obviously enhanced ( T C = 2.79  K). In addition, it is found that the incommensurate charge-density-wave (ICDW) disappears while the commensurate charge-density-wave (CCDW) shifts to about 96.2 K with the intercalation of a little of Ni. It clearly indicates that there is a competition between superconductivity (SC) and charge-density-wave (CDW) order for 2H-TaSe2 system and that between SC and ICDW is more drastic.