Efficient Room-Temperature Cooling with Magnets

Efficient Room-Temperature Cooling with Magnets

Boeije, M.F.J. (TU Delft RST/Fundamental Aspects of Materials and Energy)
Roy, P. (Radboud Universiteit Nijmegen)
Guillou, F. (TU Delft RST/Fundamental Aspects of Materials and Energy; European Synchrotron Radiation Facility)
Yibole, H.
Miao, X.F. (TU Delft RST/Fundamental Aspects of Materials and Energy)
Caron, L. (TU Delft RST/Fundamental Aspects of Materials and Energy; Max Planck Institute for Chemical Physics of Solids)
Banerjee, D. (European Synchrotron Radiation Facility)
van Dijk, N.H. (TU Delft RST/Fundamental Aspects of Materials and Energy)
de Groot, R.M. (Electronic Structure of Materials; Radboud Universiteit Nijmegen)
Brück, E.H. (TU Delft RST/Fundamental Aspects of Materials and Energy)

2016-07-26

Magnetic cooling is a highly efficient refrigeration technique with the potential to replace the traditional vapor compression cycle. It is based on the magnetocaloric effect, which is associated with the temperature change of a material when placed in a magnetic field. We present experimental evidence for the origin of the giant entropy change found in the most promising materials, in the form of an electronic reconstruction caused by the competition between magnetism and bonding. The effect manifests itself as a redistribution of the electron density, which was measured by X-ray absorption and diffraction on MnFe(P,Si,B). The electronic redistribution is consistent with the formation of a covalent bond, resulting in a large drop in the Fe magnetic moments. The simultaneous change in bond length and strength, magnetism, and electron density provides the basis of the giant magnetocaloric effect. This new understanding of the mechanism of first order magneto-elastic phase transitions provides an essential step for new and improved magnetic refrigerants.

http://resolver.tudelft.nl/uuid:eb8cb864-b0fd-4115-8e85-6595854b5970

https://doi.org/10.1021/acs.chemmater.6b00518

0897-4756

Chemistry of Materials, 28 (14), 4901-4905

Institutional Repository

journal article

© 2016 M.F.J. Boeije, P. Roy, F. Guillou, H. Yibole, X.F. Miao, L. Caron, D. Banerjee, N.H. van Dijk, R.M. de Groot, E.H. Brück