Anomalous high-field metamagnetism based on the quadrupole interaction in TmCu2

We measured the high-field magnetization of TmCu2 with the orthorhombic structure. A metamagnetic transition with a large hysteresis was observed for the field along the a-axis. This metamagnetic transition is not related to the antiferromagnetic order, which was observed even above the Neel temperature of 6.3 K. After the metamagnetic transition, the magnetization curve is not similar to the easy-axis (b-axis) magnetization, but is similar to the magnetization for the field tilted by 60deg from the a-axis. Except this result, the character of this metamagnetism is similar to the previous metamagnetism of RCu2 (R=Ce, Pr, Dy, Tb) based on the quadrupole moment. (author)