Eur. Phys. J. B 46, 281-287 (2005)
https://doi.org/10.1140/epjb/e2005-00245-9

Symmetry-dependent Mn-magnetism in Al_69.8Pd_12.1Mn_18.1

Laboratorium für Festkörperphysik, ETH Zürich, 8093 Zürich, Switzerland

Corresponding author: ^a gavilano@solid.phys.ethz.ch

Received: 23 September 2004
Revised: 17 June 2005
Published online: 11 August 2005

Abstract

We investigated the stability of magnetic moments in Al_69.8Pd_12.1Mn_18.1. This alloy exists in both, the icosahedral (i) and the decagonal (d) quasicrystalline form. The transition from the i- to the d-phase is achieved by a simple heat treatment. We present the results of measurements of the ²⁷Al NMR-response, the dc magnetic susceptibility, and the low-temperature specific heat of both phases. In the icosahedral compound, the majority of the Mn ions carries a magnetic moment. Their number is reduced by approximately a factor of two by transforming the alloy to its decagonal variety. For both compounds, we have indications for two different local environments of the Al nuclei. The first reflects a low density of states of conduction electrons and a weak coupling of the Al nuclei to the Mn-moments. The second type of environment implies a large d-electron density of states at the Fermi level and a strong coupling to the magnetic Mn moments. Spin-glass freezing transitions are observed at  K for the decagonal, and K for the icosahedral phase.