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 co ntain a high amount of vacancies depending on the annealing temperature and the quench rate. As shown before [M. Scheffer, R. Luck, Proceedings Aperio dic '97, 1998, pp. 469-472], these vacancies result in a change from a diam agnetic to a paramagnetic state at room temperature. We investigated the be haviour of the magnetic moments at low temperatures of a quenched and an an nealed sample. At this temperatures a strong decrease of the total magnetic moment after the annealing was observed. The number and the magnitude of t he magnetic moments were determined by measurements of the field and temper ature: dependence of the total magnetic moment. Evaluation of the data yiel ds 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. (C) 2000 Elsevier Science B.V. All rights reserved.