Mechanically milled Sn and Al–Cu–Fe quasicrystals nanocomposites: Exploring the interplay between structural evolution, magnetic softness and thermoelectric efficiency

Abstract

Mechanically milled Sn and Al–Cu–Fe icosahedral quasicrystals (IQC) nanocomposites with varying Sn volume fractions (0%, 10%, 20% and 30%, designated as IQC, IQC-10Sn, IQC-20Sn and IQC-30Sn) were synthesized to investigate the influence of Sn content on their structural, magnetic, and thermoelectric properties. Structural analysis confirmed the presence of the IQC phase alongside a crystalline B2-Al (Cu,Fe) phase, with the IQC phase exhibiting high ordering as indicated by the superlattice reflection (311111). Microstructural characterization revealed large grains in pure IQC, while Sn incorporation led to the formation of smaller grains and rod-like microstructure. All samples displayed soft ferromagnetic behavior with low coercivity and remanent magnetization. The Curie temperature decreased with higher Sn concentrations, correlating with grain size reduction (from 48 nm to 12 nm) and weakened exchange interactions. The anisotropy constant, derived from the law of approach to saturation, peaked for IQC-10Sn, (9.1 × 103 erg/g at 300 K and 23.5 × 103 erg/g at 2 K) and gradually declined with increased Sn content. Thermoelectric performance was optimized in IQC-30Sn, which exhibited the lowest thermal conductivity and the highest figure of merit (5.2 × 10−3 at 300 K). Moderate Sn doping (IQC-10Sn and IQC-20Sn) enhanced magnetic properties via domain structuring and anisotropy, whereas higher doping (IQC-30Sn) improved thermoelectric efficiency by facilitating charge and phonon transport. These findings demonstrate that mechanically milled Sn and Al–Cu–Fe IQC nanocomposites can simultaneously tailor magnetic and thermoelectric performance, offering a promising pathway for developing advanced IQC-based nanocomposites for multifunctional applications. © 2025 Elsevier B.V.