“…In our laboratory, several important high T c superconductors have been synthesized under high pressure as single crystals or as polycrystalline samples. This includes YBa 2 Cu 4 O 8 (Y124) [1] and Y 2 Ba 4 Cu 7 O 15Àx (Y247) [2,3], HgBa 2 Ca nÀ1 Cu n O 2nþ2þ (Hg12(n À 1)n) [4], MgB 2 [5], and recently discovered REFeAsO (RE1111; RE ¼ La, Pr, Nd, Sm, Gd) [6,7] superconductors. Many laboratories used the high-pressure techniques for the synthesis of RE1111 compounds [8][9][10][11][12][13][14][15].…”