High-pressure synthesis of cubic AuBe_5-type YbCi_5-xGa_x(0<=x<=0.7)

摘要

YbCu_5-xGa_x with the cubic AuBe_5-type structure has been prepared by high-pressure technique for the first time. By annealing under 1.5 GPa and 650 deg. C for 1 h, a cubic YbCi_5-xGa_x phase can be formed in the Ga-substitution range 0<=x<=0.7. Its lattice constant increases almost linearly with Ga content. Except for cubic ybCu_5 with x=0, the magnetic susceptibility of cubic YbCu_5-xGa_x with x<=0.1 follows the Curie-Weiss law in temperature range form 4.2 to 300 K, indicating that Yb ion is in a trivalent state (4f~13, J=7/2) similar to what is observed in cubic YbCu_5-xAl_x.