Magnetic irreversibility and a marginal phase transition in UCu₂Ge₂

Abstract

The ferromagnetic compound UCu₂Ge₂ (Tc ≈ 105K) has an additional low-temperature phase transition which is quite marginal and depends crucially on heat treatment. This, together with the cooperative response of domains themselves, leads to the interesting magnetic behaviour of this compound. The latter kind of magnetic response possesses interesting metastable character and has phenomenological similarity with spin-glass systems and hard type II superconductors.