Giant and reversible low field magnetocaloric effect in LiHoF₄ compound

Area of Science:

• Materials Science
• Thermodynamics
• Applied Physics

Background:

• Cryogenic refrigeration is vital for various industrial applications.
• Magnetic refrigeration offers high efficiency and environmental benefits over traditional methods.
• Developing effective magnetocaloric materials for low magnetic fields is crucial for practical applications.

Purpose of the Study:

• To investigate the magnetocaloric properties of LiHoF4.
• To assess its potential as a cryogenic magnetic refrigerant.
• To explore its performance under low applied magnetic fields.

Main Methods:

• A polycrystalline LiHoF4 compound was synthesized using an improved solid-state reaction method.
• The material underwent a second-order phase transition below 2 K.
• Magnetocaloric effect was measured under varying low magnetic fields (0.6 T, 1.0 T, 2.0 T).

Main Results:

• An unexpected giant low-field magnetocaloric effect was observed in LiHoF4.
• Maximum magnetic entropy changes reached 11.0, 19.0, and 25.9 J kg⁻¹ K⁻¹ for field changes of 0.6 T, 1.0 T, and 2.0 T, respectively.
• The observed effect was giant and reversible.

Conclusions:

• LiHoF4 demonstrates significant potential as a practical cryogenic magnetic refrigerant.
• Its high performance under low magnetic fields simplifies system design and reduces costs.
• This material is a leading candidate for future low-field magnetic refrigeration technologies.