Yb_1+xIn_1-xCu₄の合成と物性―強磁場磁化過程における二段階の磁気異常―

抄録

We report synthesis and characterization of structural and physical properties in YbInCu₄ and Yb-rich Yb_1+xIn_1-xCu₄. We have measured the powder X-ray diffraction, the temperature dependence of the magnetic susceptibility between 2 and 300 K in the magnetic field of 1 T, the high-field magnetization up to 72 T and the temperature dependence of the electrical resistivity in the magnetic field of 0 and 14 T to study the change of physical properties by substitution and to understand the origin of the valence transition.

The powder X-ray diffraction patterns suggest that Yb_1+xIn_1-xCu₄ crystallized in the cubic C15b-type Laves structure. We newly discovered a two-step magnetic anomaly in the high-field magnetization process interpreted by crystal field splitting effects. We finally made a magnetic phase diagram in H-x, which is consisting of 4 phases. Three phase boundaries are defined by valence transition from Yb valence fluctuation to Yb trivalent localized magnetism, change of the ground state due to crystal field splitting effects and disturbance of Kondo lattice.