METASTABLE MAGNETIC RESPONSE OF UCU2GE2

We present a detailed study of magnetization in UCu2Ge2, a system that undergoes a ferromagnetic to antiferromagnetic transition as a functi on of temperature. The nature of the ferromagnetic and antiferromagnet ic states involved, and also of the phase transition, do not seem to b e conventional. Marked irreversibility is observed in the low-temperat ure antiferromagnetic state in an external field up to 2T, and distinc t irreversibility exists even for the ferromagnetic state in the low-f ield regime (H less-than-or-equal-to 50 mT).