Fermi Surface Property and Characteristic Crystalline Electric Field Effect in PrIr2Zn20

Abstract

We measured the de Haas–van Alphen (dHvA) oscillations, electrical resistivity, magnetic susceptibility, magnetization, and specific heat of PrIr 2 Zn 20 , which has recently been suggested as a heavy-fermion superconductor. Several dHvA branches with small frequencies ranging from 0.33×10 6 to 8.00×10 6 Oe were detected in the dHvA experiment, which were well explained by the results of energy band calculations for LaIr 2 Zn 20 using the lattice parameter of PrIr 2 Zn 20 . Moreover, the cyclotron effective mass is small, i.e., less than 1 m 0 ( m 0 : rest mass of an electron). This means that 4 f electrons are fully localized and do not contribute to the Fermi surface. Similar dHvA results were obtained for the reference compound LuIr 2 Zn 20 . Thus, superconductivity in PrIr 2 Zn 20 , which has been observed very recently below 0.05 K, is not due to heavy quasiparticles. In fact, the present superconductivity disappears at a magnetic field of 20 Oe. From the experimental results of magnetic susceptibili...