A cool new way to chill: The future of solid-state cooling

Strong coupling between localized atomic vibrations and spin fluctuations increases the absorption and release of heat, shown from the bottom to the top, in a magnetic shape-memory alloy, improving its capacity for solid-state cooling. Credit: Phoenix Pleasant/ORNL, U.S. Dept. of Energy.

Scientists at Oak Ridge National Laboratory are exploring a new kind of material that could revolutionize how we cool our homes, cars, and electronics.

This innovation, called solid-state cooling, promises to be more efficient and environmentally friendly than traditional methods. Here’s how it works and why it’s so exciting.

What is Solid-State Cooling?

Solid-state cooling uses special materials that absorb and release heat when exposed to a magnetic field, eliminating the need for traditional refrigerants and moving parts.

This makes the system quieter, more compact, and able to precisely control temperatures.

The research team focused on a material known as a nickel-cobalt-manganese-indium magnetic shape-memory alloy.

This material can change its shape and return to its original form when heated or exposed to a magnetic field.

This shape change allows the material to absorb and release heat, a process known as the magnetocaloric effect.

When the material is subjected to a magnetic field, it undergoes a phase transition. During this transition, it absorbs heat from its surroundings and then releases it, cooling the environment.

The key to this material’s effectiveness lies in its atomic structure, which is near a disordered state called ferroic glassy states. These states enhance the material’s ability to store and release heat.

The researchers used advanced tools to study the material at the atomic level. They discovered that in small regions within the material, there are synchronized patterns of vibrations (phonons) and magnetic waves (magnons).

These patterns, called localized hybrid magnon-phonon modes, significantly affect the material’s thermal properties.

The team found that these modes cause the vibrations to shift when a magnetic field is applied, altering the material’s stability and behavior. This shift increases the material’s ability to store and release heat, making it an excellent candidate for solid-state cooling.

By understanding these localized hybrid modes, scientists can enhance the material’s cooling capacity.

In fact, the research revealed that the cooling power of this magnetic shape-memory alloy is tripled due to the heat stored in these localized modes.

This discovery opens the door to creating better materials for solid-state cooling, which could eventually replace traditional refrigerants and mechanical parts.

Traditional cooling methods rely on refrigerants that can be harmful to the environment and involve complex mechanical systems that can be noisy and prone to breakdowns.

Solid-state cooling offers a cleaner, quieter, and more efficient alternative.

By advancing our understanding of materials like the magnetic shape-memory alloy, we move closer to a future where our cooling systems are both high-performing and eco-friendly.

In summary, the work of the Oak Ridge National Laboratory team has shed light on how we can use innovative materials to create better cooling technologies.

This research not only provides a glimpse into the future of refrigeration but also represents a significant step towards more sustainable living.