The high temperature preparation and property measurements of CaTaN2: A ternary superconducting nitride

Article abstract of DOI:10.1016/S0022-3697(96)00066-2

Highly crystalline CaTaN₂ was prepared by the reaction of Ca(NH₂)₂ and Ta₃N₅ in a specially designed reaction vessel at high temperatures (> 1300°C), Even when reaction conditions varied considerably, the samples were always contaminated by small amounts of Ca₂TaN₃, TaN, or TaN_0.1. SQUID measurements obtained on a sample contaminated by Ca₂TaN₃ and a sample contaminated by TaN and TaN_0.1 showed superconducting transitions at 9.6 K and 9.1 K, respectively. Resistivity measurements carried out on a sintered pellet of CaTaN₂ contaminated by TaN_0.1 showed a ρ(300 K) = 0.0147 ω cm and weakly rising resistivity with lower temperatures, likely due to the random alignment of the polycrystalline grains.