Magnetic Properties and de Haas-van Alphen Effect of PrNi₂Al₅

We have succeeded in growing a high-quality single crystal of PrNi₂Al₅, and have measured the electrical resistivity, magnetic susceptibility, magnetization and specific heat. Any magnetic phase transition has not been observed. The crystalline-electric-field (CEF) scheme has been estimated by using the reciprocal susceptibility and a magnetic part of the specific heat. The magnetic anisotropy has been well explained by the CEF effect. The analytical result of the CEF effect shows that this compound has a singlet ground state and that the CEF energy in 4f electrons from the ground state to the first excited state is 43 K. The Fermi surfaces and the cyclotron effective masses have been investigated by means of de Haas-van Alphen effect. It is found that the Fermi surfaces of PrNi₂Al₅ are almost the same as those of LaNi₂Al₅.