EVIDENCE OF A SPIN-GLASS TRANSITION IN THE QUASI-CRYSTAL AL73MN21SI6

We give a definite answer to the question whether or not the quasicrystal i-Al73Mn21Si6 is a true three-dimensional spin glass by measuring the linear (ac and dc) and dc nonlinear susceptibilities [A3(T),...]. We show that the magnetic correlations expand over large distances with decreasing T and that A3(T) diverges following the spin-glass transition scaling law with finite Tc. From A3 and dc we deduce separately and in the H=0 field limit the number (1.3% of the Mn concentration) and the moment (large, 7.5B) of the magnetic entities, which can be attributed to Mn clusters. © 1990 The American Physical Society.