半導体及び超伝導体の高圧合成と物性

抄録

Using a wedge-type cubic anvil high pressure apparatus, metal-IVA and -VA group compounds have systematically been prepared at high temperatures and high pressures. In this paper we mainly report the electrical properties of the compounds with skutterudite (CoAs₃-type) structure prepared at high pressure. CoP₃ and CeRu₄P₁₂ behave as a semiconductor. NiP₃ is a metal. LaRu₄P₁₂ is a superconductor with T_c of 7 K. The electrical resistivity of alloys La_1-xCe_xRu₄P₁₂ rapidly increases with increasing x. The metal to semiconductor transition is observed at around X=0. 6. PrRu₄P₁₂ shows the electrical anomaly due to the metal-insulator transition at around 60 K. The T_c's of new superconductors LaRu₄As₁₂ and LaRu₄Sb₁₂ are 10. 3 K and 2. 8 K, respectively. LaRu₄As₁₂ has the highest T_c in the skutterudite compounds. PrRu₄As₁₂ is an interesting superconductor containing the magnetic rare earth with T_c of 2. 5 K though PrRu₄P₁₂ behaves as the semiconductor below 60 K. We have found the new compound superconductors, ZrRuSi, ZrRuGe, ZrRu₄P₁₂, LaRu₄As₁₂ and ZrRhSi, with T_c of above 10 K in metal-IVA and -VA group compounds prepared at high pressure.