Spin glass behavior in a decagonal quasicrystal Al-Mn-Fe-Ge system

The magnetic behavior of a decagonal quasicrystal Al40Mn25Fe15Ge20 system h as been investigated by Mossbauer spectroscopy, magnetization and AC suscep tibility measurements. Magnetization measured at low fields as a function o f temperature shows a cusp-like peak around 41 K. AC susceptibility also sh ows a sharp cusp, and the cusp shifts to a higher temperature as the freque ncy increases. These results strongly suggested that Al40Mn25Fe15Ge20 is a spin glass system with T-g = 41 K. From the temperature dependence of the M ossbauer spectrum, we observed the appearance of a hyperfine field below ar ound 50 K. The temperature is a little higher than the cusp temperature, wh ich is rather usual in spin glass systems.