Single Crystal growth of mixed anion Zr(P, Se)(2) superconductor and related materials

A new method to grow single crystals of PbFCl-type mixed anion AP(2-x)X(x) (A = Zr, Hf, X = S, Se) superconductor is examined. Using a wedge-type, cubic-anvil, high-pressure apparatus, single crystals of ZrP1.25Se0.75 (A = Zr, X = Se) were grain grown from nominal composition melts under a pressure of 2.0 GPa. Obtained Plate-like single crystal with approximate edge sizes of 160 x 160 x 20 mu m(3) was measured on electron probe microanalysis and X-ray diffraction indicate that the as-grown boules are a single phase ZrP1.25Se0.75. Superconducting transition temperature (T-c) is 6.31 K for ZrP1.25Se0.75 single crystal. It also succeeded in single crystal growth of substitution of nonmagnetic rare earth atoms for A (A = Zr) site, T-c = 6.91 K was reached in the (Zr0.50Lu0.50)PSe nominal composition. In this paper, the crystal growth of these compound are also reported.