X-ray diffuse scattering of an Al-Cu-Fe single quasicrystal

Abstract

We present the results of the first X-ray measurement of diffuse scattering of an Al-Cu-Fe single quasicrystal. The measurement was carried out at room temperature using a specimen quenched from 1098 K. This specimen contains neither the linear phasons nor the quenched phasons having relatively large amplitude such as those contained in an icosahedral glass model. Contour maps of the diffuse scattering intensity have almost the same rhombic shape for all the four diffraction spots measured in this work. This result may be interpreted, if the specimen contains only a very few amounts of both thermal and quenched random phasons. It is also found that the diffuse scattering intensity is proportional to the nth power of q, where q means the difference in wave number vector from the corresponding Bragg reflection point. The exponent n is estimated to be -2 for the T-direction and between -3 and -4 for L-direction. The latter relation seems not to be explained by either phonon and phason strains assumed theoretically until now.