Magnetic anisotropy of pure and doped YbInCu4compounds at ambient and high pressures

Abstract

The susceptibility and high-field magnetization of single-crystallineYb1−xYxInCu4(x = 0,0.2 and 0.3) samples have been measured for different fieldorientations at ambient and high pressures. The compounds withx = 0 and0.2 undergo a first-order valence transition from the intermediate-valence state to thetrivalent state on increasing either temperature or magnetic field. The magnetizationand susceptibility of these compounds have appreciable anisotropy in both states. Themagnetic phase diagram of Yb1−xYxInCu4determined at ambient pressure is also anisotropic, which is explained bythe crystal-field calculations for the free Yb ion in the high-temperaturephase. Moreover, the low-temperature magnetization process for x = 0.2and 0.3 has been measured in low fields under high pressure; it shows anisotropicferromagnetic ordering.