High-Tc Phase of PrO0.5F0.5BiS2 single crystal induced by uniaxial   pressure
  We demonstrated a pressure-induced phase transition from a low-Tc phase (3.5 K) to a high-Tc phase (8.7 K) in single crystalline PrO0.5F0.5BiS2. The high-Tc phase is easily observed even at 0.7 GPa by uniaxial pressure obtained from a geometric effect of a single crystal with an extremely-thin thickness. For this phase transition, superconducting anisotropy and the coherence length along the c axis change from {\gamma} = 20 to 9.3 and from {\xi}c = 0.56 to 0.71 nm respectively. It is suggested that a shrinkage in the c lattice constant by applied uniaxial pressure enhances the three dimensionality in the superconducting state. 
Masaya Fujioka, Masanori Nagao, Saleem J. Denholme, Masashi Tanaka,   Hiroyuki Takeya, Takahide Yamaguchi, Yoshihiko Takano
cond-mat.supr-con