A team of researchers from TU Braunschweig and Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has discovered a strong magnetocaloric effect in the natural mineral atacamite. This finding could pave the way for new, energy-efficient cooling systems that do not rely on harmful gases or complex mechanical parts.

What Makes Atacamite Special?

Atacamite is a copper-based mineral known for its vivid green colour. Found originally in Chile’s Atacama Desert, it contains copper ions arranged in a zig-zag pattern called “sawtooth chains”. These ions behave like tiny magnets, each with a direction (or spin).

However, the triangular shape of the chains prevents these spins from aligning perfectly. This creates a condition known as magnetic frustration. As a result, the ions form an ordered structure only at extremely low temperatures, below 9 Kelvin (−264°C).

Strong Cooling Effect When Exposed to Magnetic Fields

When atacamite was tested under pulsed magnetic fields, it cooled dramatically—almost 50% lower than its original temperature. This is known as the magnetocaloric effect, where a material changes temperature due to a change in magnetic entropy.

This effect is stronger in atacamite than expected, making the discovery particularly exciting. Most magnetically frustrated materials do not behave this way. In atacamite, the external magnetic field breaks the delicate spin structure, causing the system to release heat and cool down.

Sustainable Cooling Without Gas Refrigerants

Unlike traditional fridges that rely on compressing and expanding chemical gases, magnetocaloric materials offer a cleaner alternative. They can cool things down using magnetic fields only, without emissions or moving parts.

This makes the technology highly attractive for sustainable product design, such as wearable devices, compact electronics, or packaging that needs precise temperature control.

Outlook for Material Innovation

Although atacamite itself is not suitable for mass production, the study provides a model for creating synthetic materials with similar properties. These materials could lead to low-energy, recyclable, and even biobased cooling systems.

Designers working in product development, smart packaging, or consumer electronics may find this research particularly valuable. It supports the move toward sustainable innovation and opens new directions for thermal management in design.

Source: TU Braunschweig & HZDR
Image: B. Schröder/HZDR