Engineering of a Layered Ferromagnet via Graphitization: An Overlooked Polymorph of GdAlSi

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Layered magnets possess tunable functional properties but are limited in variety.
• Graphitization is a method for stabilizing 2D layered structures, primarily explored in cubic materials.
• Discovering new layered magnetic materials is crucial for expanding their applications.

Purpose of the Study:

• To explore graphitization as a route to synthesize new layered materials beyond cubic structures.
• To investigate the synthesis and properties of a novel layered magnet, Gadolinium Aluminum Silicon (GdAlSi).
• To compare the magnetic properties of layered and non-layered polymorphs of GdAlSi.

Main Methods:

• Theoretical and experimental investigation of graphitization for non-cubic materials.
• Synthesis of epitaxial GdAlSi films on silicon substrates.
• Characterization of structural stability, magnetic properties, and electron transport phenomena.

Main Results:

• Successful synthesis of layered GdAlSi films with a critical thickness of approximately 20 monolayers.
• The layered GdAlSi polymorph exhibits ferromagnetism, unlike its non-layered counterpart.
• Electron transport measurements confirmed ferromagnetism through negative magnetoresistance and the anomalous Hall effect.

Conclusions:

• Graphitization is a viable and powerful strategy for designing novel functional layered materials.
• The newly discovered layered magnet GdAlSi demonstrates promising ferromagnetic properties.
• This work expands the scope of graphitization beyond cubic materials for layered material design.