Structural analysis of Gd₆FeBi₂ from single-crystal X-ray diffraction methods and electronic structure calculations

Area of Science:

• Solid State Physics
• Materials Science
• Crystallography
• Magnetism

Background:

• Understanding the relationship between crystal structure and magnetic properties is crucial for developing new magnetic materials.
• Rare-earth intermetallic compounds often exhibit interesting magnetic behaviors influenced by their crystal structure and electronic interactions.
• The Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction is a common mechanism governing magnetic exchange in such materials.

Purpose of the Study:

• To characterize the crystal structure of gadolinium iron bismuthide (Gd$_{6}$FeBi$_{2}$) using experimental and computational methods.
• To investigate the origin of the unusually high magnetic ordering temperature observed in this compound.
• To elucidate the electronic structure and magnetic interactions responsible for the material's magnetic response.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the precise crystal structure of Gd$_{6}$FeBi$_{2}$.
• First-principles calculations were utilized to analyze the electronic structure and magnetic properties.
• Analysis focused on atomic arrangements, magnetic moments, and interatomic electronic hybridization.

Main Results:

• Gd$_{6}$FeBi$_{2}$ crystallizes in a structure isotypic with Zr$_{6}$CoAl$_{2}$, featuring tricapped trigonal prisms of Gd atoms centered by Fe and Bi.
• The compound exhibits a high magnetic ordering temperature (around 350 K), significantly higher than related phases.
• First-principles calculations revealed an unexpectedly large gadolinium magnetic moment, attributed to strong Gd 5d-Fe 3d hybridization.

Conclusions:

• The high magnetic ordering temperature in Gd$_{6}$FeBi$_{2}$ is primarily driven by strong Gd 5d-Fe 3d hybridization, not weak Gd-Bi interactions.
• The enhanced Gd magnetic moment contributes significantly to the observed magnetic properties.
• This study provides critical insights into the structure-property relationships governing magnetism in rare-earth intermetallic compounds.