The Influence of Tensile Deformation and Atomic Short-Range Order on the Susceptibility of CuMn Spin Glasses

The magnetic ac-susceptibility of CuMn-alloys, χ(T), proves to be a very sensitive probe, particularly near the cusp defining the spin glass temperature Tf[1], to detect variations of the structural state χ(T) increases with an increasing degree of atomic short – range order (SRO). It is shown that for well annealed specimens the amount of SRO and simultaneously χ(Tf) pass a minimum as function of the quenching temperature Tq at about Tq = 450°C. The normalized χ(T)-curves considered as functions of the reduced temperaturesT/Tf are broader for a smaller amount of SRO. A plastic tensile deformation at room temperatrue causes an increase in χ(T). It is detectable already for 5 at% Mn and becomes very pronounced for 13 at% Mn. The effect vanishyes completely when the SRO is dissolved by quenching the sample after an anneal at 450°C. From that it is concluded that the tensile deformation generates a vacancy concentrtation high enough to produce an otherwise unattainable amount of SRO at room temperatrue.