Spin-glass transition in Cu-Al-Mn shape-memory alloys

The magnetic properties of a set of Cu-Al-Mn shape-memory alloys are studie d. A spin freezing at low temperatures is observed in all cases. It is show n that, whereas this freezing is not a spin-glass transition for the sample s with highest Mn content(similar to 9 at. %), such a transition does actua lly exist in a specimen with 6.3 at. % Mn. For this alloy, the critical exp onents related to the transition are obtained from scaling of de and ac sus ceptibility measurements. Finally, the effects of quenches from different t emperatures on the magnetic properties of the same alloy are investigated a nd discussed. [S0163-1829(99)05017-1].