Bulk Ferromagnetic Icosahedral Quasicrystals without Rapid Quenching

Area of Science:

• Condensed Matter Physics
• Materials Science
• Magnetism

Background:

• Ferromagnetism is understood in periodic and amorphous materials.
• Critical behavior in quasiperiodic systems remains elusive.
• Previous ferromagnetic icosahedral quasicrystals (iQCs) were metastable, limiting study.

Purpose of the Study:

• To realize bulk, annealable ferromagnetic iQCs.
• To investigate the magnetic critical behavior in these novel quasicrystals.
• To understand the factors governing magnetic criticality in quasiperiodic systems.

Main Methods:

• Compositional tuning of Au-Cu-Al-In-R (R = Gd, Tb, Dy) alloys.
• Conventional arc melting and controlled annealing.
• Analysis of magnetic critical behavior and critical exponents.

Main Results:

• Successfully synthesized single-phase, annealable ferromagnetic iQCs.
• Observed distinct magnetic critical behaviors based on rare-earth elements (Gd, Tb, Dy).
• Gd-based iQCs showed enhanced critical exponent δ, deviating from mean-field behavior.

Conclusions:

• Magnetic criticality in iQCs depends on the interplay between quasiperiodicity and local spin symmetry, not just quasiperiodic order.
• Quasiperiodic solids offer a tunable platform for exploring non-mean-field critical behavior.
• This work establishes a new class of materials for studying fundamental magnetic phenomena.