Influence of vacancies on the magnetic properties of icosahedral Al7.10Pd20.0Mn9.0

Quenched samples of the icosahedral alloy of the ternary system Al–Pd–Mn contain a high amount of vacancies depending on the annealing temperature and the quench rate. As shown before [M. Scheffer, R. Lück, Proceedings Aperiodic ’97, 1998, pp. 469–472], these vacancies result in a change from a diamagnetic to a paramagnetic state at room temperature. We investigated the behaviour of the magnetic moments at low temperatures of a quenched and an annealed sample. At this temperatures a strong decrease of the total magnetic moment after the annealing was observed. The number and the magnitude of the magnetic moments were determined by measurements of the field and temperature dependence of the total magnetic moment. Evaluation of the data yields only a small number of magnetic moments. We relate the observed moments to a high amount of vacancies and to a disorder of Al and Mn, respectively.