Anomalous magnetic behaviour of NdCu2 in high magnetic fields

Some of the RCu2 compounds (R = Ce,Pr,Tb,Dy) with easy a-axis show an irrev ersible change of the easy axis into the c-direction in high magnetic field s. This metamagnetic "axis conversion" is caused by a strong magneto-elasti c coupling in the ac-plane. With NdCu2 a similar magnetic behaviour was fou nd for the first time in a system with an easy axis perpendicular to the ac -plane. We present results of magnetization in static magnetic fields up to 14T. The minimum conversion field is mu H-0(crit) = 12.5 T which is higher than in the other compounds. At low temperatures the magnetic axis convers ion coincides with the transition into the induced ferromagnetic state. Mag netization measurements were also carried out in pulsed fields up to 50T. T hey show an almost linear increase of the conversion fields with temperatur e which gives a strong evidence that the conversion is caused by an effecti ve quadrupolar coupling. In addition, comparing the results of static and p ulsed field experiments, an influence of field duration on the conversion p rocess was found. The high-precision pulsed field magnetization experiments were done in the Dresden high magnetic field facility (HLD). (C) 2001 Else vier Science B.V. All rights reserved.