Effect of nickel impurities on charge-density-wave formation in TaS3

Introduction of nickel impurities into TaS3 has the effect of smearing the charge-density-wave transitions in TaS3 of both orthorhombic and monoclinic phases. The orthorhombic doped crystals show non-Ohmic conductivity beyond threshold fields that are much larger than the threshold field of the pure phase, possibly due to additional pinning of the charge-density wave by nickel impurities. The charge-density-wave state is completely destroyed as 10 at.% or more Ta atoms are replaced by Ni atoms and metallic behavior between 4.2 and 300 K is observed in these cases.