Magneto-Impedance measurements in thin films of the Spin-Glass Cu100-xMnxAu13.5 (x=6.75 and 13.5) alloys

Magneto-impedance measurements (MI) were carried out on thin-films of Cu100-xMnxAu13.5 (x = 6.75 and 13.5). The sample with x = 6.75 (13.5) undergoes a phase transition to a spin-glass state below a glass temperature of about T-G = 31 K (55 K). The MI measurements were carried out for temperatures (T) from 300 K down to 5 K in applied magnetic fields in the range of +/- 3.5 kOe and for an ac electric current with frequency of 9.0 MHz. Shortrange interaction and spin-fluctuations yielded non-vanishing values for the MI data for all values of T. The transverse magnetic permeability (mu(T)) was obtained for both sample compositions demonstrating that MI is a suitable technique to study canonical spin-glasses in the MHz regime. Moreover, it was observed that the spinfluctuations in very short time scale (similar to 10(-7) s) are important down to the lowest temperature investigated of 5 K. The transverse magnetic susceptibility, mu(T), showed a minimum near the freezing temperature.