Materials that change temperature in magnetic fields could lead to new refrigeration technologies that reduce the use of greenhouse gases. This thanks to new research at the U.S. Department of Energy's Argonne National Laboratory and Ames National Laboratory.

Scientists carrying out X-ray experimentation at the Advanced Photon Source at Argonne — USA's most powerful source of X-rays for research — are learning new information about magnetocaloric materials that have potential for environmentally friendly magnetic refrigeration systems, reveals the organization’s press release. Magnetic refrigeration is a clean technology that uses magnetic fields to manipulate the degree of ordering (or entropy) of electronic or nuclear magnetic dipoles in order to reduce a material's temperature and allow the material to serve as a refrigerant.

New materials for refrigeration based on gadolinium-germanium-silicon alloys display a giant magnetocaloric effect (a change in temperature accompanying a change in a material's magnetization) due to unusual coupling between the material's magnetism and chemical structure. Understanding this coupling is essential to moving this technology from the laboratory to the household.

"As a result of this work we now have a better understanding of the role of nonmagnetic elements, such as germanium, in enhancing magnetic interactions between the rare-earth metals in these materials,” said co-author and Ames Laboratory senior scientist Vitalij Pecharsky.