Superconductivity of MRhSi (M = Ti, Zr and Hf) prepared at high pressure

Using a wedge-type cubic-anvil high pressure apparatus, ternary rhodium sil icides MRhSi (M = Ti, Zr and Hf) and alloys ZrRh1-xRuxSi (x = 0.1, 0.3 and 0.5) with a Co2P-type orthorhombic structure have been prepared by reaction of stoichiometric amounts of each metal and silicon powders at around 4 GP a and above 1200 degrees C. The electrical resistivity and the d.c. magneti c susceptibility of the ternary rhodium silicides and the alloys have been measured at low temperatures. Superconducting transition temperatures (T-c) in MRhSi (M = Ti, Zr and Hf) are 5.1, 10.3 and 2.3 K, respectively. These ternary rhodium silicides are new superconductors. The T-c (=10.3 K) of ZrR hSi is highest among many compounds with the Co2P-type structure. (C) 1998 Elsevier Science Ltd. All rights reserved.