2009 年 78 巻 12 号 p. 123711
We measured the high-field magnetization and de Haas–van Alphen (dHvA) oscillations for YbIr2Zn20 with a cubic crystal structure, together with the electrical resistivity and magnetic susceptibility. The magnetic susceptibility χ with an effective magnetic moment of Yb3+ becomes temperature-independent at low temperatures, with a broad peak at Tχmax=7.4 K for H||‹110›. The corresponding magnetization indicates a metamagnetic transition at Hm=120 kOe, consistent with a Tχmax vs Hm relation in the Ce- and U-based heavy fermion compounds. The large cyclotron masses of 4–27 m0 are detected in the dHvA experiment, and are found to be reduced at magnetic fields higher than Hm=120 kOe. The resistivity follows the Fermi liquid relation ρ=ρ0+AT2 under magnetic field, and the \\sqrtA value is also found to have a maximum at Hm as a function of magnetic field. From the present experimental results, together with the results of 4f-itinerant energy band calculations, the 4f electrons are found to contribute to the heavy fermion state in YbIr2Zn20.