High-Entropy Magnet Enabling Distinctive Thermal Expansions in Intermetallic Compounds

Area of Science:

• Materials Science
• Condensed Matter Physics
• Magnetism

Background:

• High-entropy strategy is increasingly used for functional materials.
• High-entropy magnets (HEMs) integrate diverse magnetic compounds into a single phase.
• HEMs are expected to exhibit unique magnetic properties.

Purpose of the Study:

• To introduce and exemplify the concept of high-entropy magnets (HEMs).
• To investigate the magnetic and thermal expansion properties of HEMs.
• To explore the potential of HEMs for novel material functionalities.

Main Methods:

• Synthesized AB2-type layered Kagome intermetallic compounds with a high-entropy composition.
• Investigated magnetic transitions using temperature-dependent measurements.
• Analyzed thermal expansion properties over a wide temperature range.

Main Results:

• Observed intricate magnetic transitions due to competing magnetic states and high-entropy site interactions.
• Demonstrated unusual transformations in thermal expansion (positive, zero, negative).
• Achieved near-zero thermal expansion (αv = -0.62 × 10^-6 K^-1) from 10-360 K in (Ti1/5Zr1/5Hf1/5Nb1/5Fe1/5)Fe2.

Conclusions:

• The HEM strategy enables the creation of materials with complex magnetic behaviors.
• Near-zero thermal expansion is achieved in a specific HEM composition, linked to magnetic moment dynamics.
• HEMs offer a promising pathway for discovering new functional solid materials.