High-Temperature Layered Modification of Mn₂In₂Se₅.

Area of Science:

• Materials Science
• Solid State Physics
• Magnetism

Background:

• Layered chalcogenides are key for developing two-dimensional magnetic systems in spintronics.
• High-spin cations like Mn²⁺ and Fe³⁺ are crucial for discovering novel magnetic compounds.

Purpose of the Study:

• To synthesize and characterize a new layered polymorph of Mn₂In₂Se₅.
• To investigate its structural stability and magnetic properties.

Main Methods:

• Synthesis of Mn₂In₂Se₅.
• Simultaneous thermal analysis and X-ray powder diffraction (XRD) at elevated temperatures.
• Thermal gravimetric analysis (TGA) and Rietveld refinement.
• Magnetization measurements.

Main Results:

• A phase transition to a trigonal lattice polymorph occurred at 711 °C.
• The new polymorph crystallizes in the Mg₂Al₂Se₅ structure type.
• An antiferromagnetic-like transition was observed at 6.3 K, with strong magnetic frustration (|θ|/T_N = 28).

Conclusions:

• The synthesized Mn₂In₂Se₅ polymorph is stable in air at high temperatures.
• The material exhibits magnetic frustration, making it a candidate for spintronic applications.