New magnetic chip cooling technology

2013/02/20 Kortabitarte Egiguren, Irati - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Fisika
• Elektronika

CIC nanoGUNE researchers have developed a new magnetic chip cooling technology based on material stress. This advance will allow a lower environmental impact than current technologies. The work has been recently published in the journal Nature Materials.

Current refrigeration systems (refrigerators, freezers or air conditioning appliances) use the compression and expansion of a gas. This system, however, is harmful to the environment and in addition the compressors used are inefficient.

One of the main possibilities currently under investigation is magnetic cooling. It consists of replacing the gas with a magnetic material and replacing the compression/expansion cycles with imanation/desimanation cycles. Magnetic cooling is based on the magnetocaloric effect, that is, on the ability of some materials to modify their temperature when applying a magnetic field. However, the application of a magnetic field causes numerous problems in current miniaturized technological devices (electronic chips, computer memories, etc. ), as the magnetic field can negatively influence nearby units. Therefore, it is essential to seek new ways of controlling magnetization.

Magnetism without magnetic fields

Luis Piedra, Andreas Berger and Odrej Hovorka, from nanoGUNE, have discovered that with the tension of the materials one can avoid the problems of applying a magnetic field. “Stretching and relaxing the material produces an effect similar to that of the magnetic field, inducing the magnetocaloric effect that cooling produces,” explains Luis Bones, head of the nanodevice team of nanoGUNE and principal researcher of this study.

“This new technology allows us to have a more local and controlled cooling method, without prejudice to the other units of the device,” added Bone.

Films of about 20 nanometers consisting of _{lanthanum, calcium, manganese and oxygen} (La0.7 _Ca0.3MnO3) have been developed. According to Bones, “the aim of this field of research is to find efficient, economic and environmentally friendly materials.”

“The idea arose at the University of Cambridge and, among several groups in the UK, France, Ukraine and Euskal Herria, we have found electronic chips, computer memories and an appropriate material to cool all these types of microelectronic applications. Technologically there would be no obstacle to the use of refrigerators, freezers... but economically it is not worth it for its size”, stressed Bone.