Periodic Oscillations of Josephson-Vortex Flow Resistance in   Oxygen-Deficient Y1Ba2Cu3Ox
  We measured the Josephson vortex flow resistance as a function of magnetic field applied parallel to the ab-planes using annealed Y1Ba2Cu3Ox intrinsic Josephson junctions having high anisotropy (around 40) by oxygen content reduction. Periodic oscillations were observed in magnetic fields above 45-58 kOe, corresponding to dense-dilute boundary for Josephson vortex lattice. The observed period of oscillations, agrees well with the increase of one fluxon per two junctions ($H_{p}$\textit{=$\Phi $}$_{0}$\textit{/2Ls}), may correspond to formation of a triangular lattice of Josephson vortices as has been reported by Ooi et al. for highly anisotropic (larger than 200) Bi-2212 intrinsic Josephson junctions. 
M. Nagao, S. Urayama, S. M. Kim, H. B. Wang, K. S. Yun, Y. Takano, T.   Hatano, I. Iguchi, T. Yamashita, M. Tachiki, H. Maed...