A new (Hg, V)-based 1212-type cuprate (Hg, V) Sr2(Y, Ca) Cu2Oz with Tc(onset) up to 110 K

We have successfully synthesized a new (Hg, V)-based 1212-type cuprate (Hg1−x V x )Sr2(Y1−y Ca y )Cu2O z . The electrical resistance measurements showed that some of the as-synthesized materials with proper Hg/V and Y/Ca ratios exhibit weak superconductivity. Oxygen-annealing significantly improved their superconducting behavior, andT c(onset) up to 110 K was observed. The lattice parameters of (Hg,V)-1212 were found to be in the order ofa=3.8415(1) A andc=11.8514(6) A. Substitu ting mercury atoms by vanadium ones results in an important increase of thea parameter and an important decrease of thec parameter compared to the known Hg-based Sr-bearing compounds. The crystal structure of (Hg, V)-1212 was refined by Rietveld refinement against X-ray powder data using the tetragonal symmetry of space groupP4/mmm. The V and Cu valence states and superconductivity in this new (Hg, V)-1212 cuprate are briefly discussed.