Materials that change temperature in magnetic fields could lead to new refrigeration technologies that reduce the use of greenhouse gases, 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 the nation'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. 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 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. Magnetic refrigeration does not rely on hydrofluorocarbons (HFCs) used in conventional refrigeration systems. HFCs are greenhouse gases that contribute to global climate change when they escape into the atmosphere.