Colossal room-temperature electrocaloric strength aided by hydrostatic pressure in lead-free multiferroic solid...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Thermodynamics

Background:

• Electrocaloric (EC) effects enable solid-state cooling with potential for miniaturization.
• Current EC materials often contain toxic elements and require high electric fields, leading to leakage and dielectric loss issues.
• Developing lead-free EC materials with improved performance is crucial for practical applications.

Purpose of the Study:

• To investigate the combined effect of hydrostatic pressure and electric fields on lead-free multiferroic materials for enhanced electrocaloric cooling.
• To theoretically demonstrate a strategy for reducing driving electric fields and improving EC strength in BiFeO3-based materials.

Main Methods:

• First-principles simulations were employed to study supertetragonal BiFe1-xCoxO3 (BFCO) solid solutions.
• The study theoretically analyzed the electrocaloric response under varying hydrostatic pressure and electric field conditions.

Main Results:

• Hydrostatic pressure was found to tune the electrocaloric effect towards room temperature.
• The application of hydrostatic pressure significantly reduces the required electric field intensity for EC effects.
• Pressurized BFCO exhibits a colossal room-temperature EC strength of approximately 1 K cm kV⁻¹, several orders of magnitude higher than in uncompressed ferroelectrics.

Conclusions:

• Concertedly applying hydrostatic pressure and electric fields is a viable strategy to overcome limitations in current electrocaloric cooling technologies.
• Lead-free multiferroic BFCO, under hydrostatic pressure, demonstrates potential for highly efficient and safe solid-state cooling applications.
• This research paves the way for practical, high-performance electrocaloric devices operating near room temperature.