Synthesis and superconducting properties of the iron oxyarsenide   TbFeAsO0.85
  The iron oxyarsenide TbFeAsO0.85 was synthesized by a high-pressure method. A high-quality polycrystalline sample was obtained and characterized by measurements of magnetic susceptibility and electrical resistivity. Bulk superconductivity with Tc of 42 K was clearly established without an F doping usually conducted to tune on superconductivity in the iron oxypnictide. 
Y.G. Shi, S. Yu, A.A. Belik, Y. Matsushita, M. Tanaka, Y. Katsuya, K.   Kobayashi, K. Yamaura, E. Takayama-Muromachi