High Phase-Purity and Composition-Tunable Ferromagnetic Icosahedral Quasicrystal

Area of Science:

• Materials Science
• Condensed Matter Physics
• Magnetism

Background:

• Icosahedral quasicrystals (i QCs) are ordered structures lacking translational symmetry.
• The magnetic properties of quasicrystals are of significant interest for fundamental research and potential applications.

Purpose of the Study:

• To discover and characterize a novel ferromagnetic icosahedral quasicrystal.
• To investigate the relationship between composition and magnetic properties in these quasicrystals.
• To elucidate the nature of the ferromagnetic transition and its tunability.

Main Methods:

• Synthesis of a high-purity Au-Ga-Dy icosahedral quasicrystal.
• Investigation of isothermal magnetization.
• Analysis of the Weiss temperature (θp) as a function of the electrons-per-atom (e/a) ratio.

Main Results:

• Discovery of a ferromagnetic Au-Ga-Dy i QC with tunable composition and high phase purity.
• Elucidation of the mean-field-like nature of the ferromagnetic transition.
• Identification of a maximum Weiss temperature at an e/a ratio of 1.70, consistent with analogous crystalline alloys (ACs).
• Demonstration of the tunability of magnetic properties based on the e/a ratio.

Conclusions:

• The magnetism of i QCs is directly dependent on the e/a ratio, which influences the Fermi energy.
• The findings validate the θp-e/a scheme for tuning magnetic properties in i QCs.
• This work opens possibilities for exploring exotic magnetic textures on quasiperiodic lattices.