Low-Dimensional Magnetic Semimetal Cr_0.65Al_1.35Se₃

Area of Science:

• Solid State Chemistry
• Materials Science
• Condensed Matter Physics

Background:

• Exploration of novel magnetic semiconductors is crucial for advancing spintronic applications.
• Understanding structure-property relationships in new materials is key to discovering unique functionalities.

Purpose of the Study:

• To discover and characterize a new magnetic semiconductor phase.
• To determine the crystal structure and physical properties of Cr$_{0.65}$Al$_{1.35}$Se$_{3}$.

Main Methods:

• Single-crystal X-ray diffraction for structural determination.
• Temperature-dependent magnetic susceptibility measurements.
• Electrical resistivity and magnetoresistance measurements.

Main Results:

• Discovery and structural characterization of Cr$_{0.65}$Al$_{1.35}$Se$_{3}$ in an orthorhombic CrGeTe$_{3}$-type structure (space group *Pnma*).
• Identification of unique T-shaped channels and puckered Se atoms within the columnar channels.
• Observation of an antiferromagnetic-type transition at ~8 K, with indications of ferromagnetic interactions due to mixed Cr/Al occupancy.
• Confirmation of semimetallic behavior and positive magnetoresistance.

Conclusions:

• Cr$_{0.65}$Al$_{1.35}$Se$_{3}$ represents a novel magnetic semiconductor with a complex crystal structure and intriguing magnetic properties.
• The mixed occupancy of Cr and Al atoms significantly influences the magnetic interactions.
• This material holds potential for further investigation in the field of magnetic semiconductors.