New magnetic materials for efficient energy conversion
FOM researchers from Delft University of Technology and Radboud University Nijmegen have designed a new type of magnetism. Strong and weak magnetism were found to be able to co-exist in successive atomic layers in a lattice. By varying the composition of the materials, the researchers designed new materials with high yields that are cheaper than current alternatives and can be used in cooling or energy conversion systems. They published their results last week in the journal Advanced Energy Materials.
The temperature of magnetic materials changes under the influence of a magnetic field: the so-called magnetocaloric effect. This occurs because an external magnetic field ensures an ordering of the magnetic moments in the material. The consequent reduction in entropy causes the material to heat up. This magnetocaloric effect forms the basis for magnetic cooling systems. The strong response of these materials can also be put to use in induction devices in which residual heat is converted into electrical energy.
Strong and weak
Professor Ekkes Brück leads the FOM Industrial Partnership Programme in which this research took place. By combining theoretical calculations and experimental studies his research team designed a material with a very strong magnetocaloric effect. In this material strong and weak magnetic sublattices of manganese and iron are embedded in alternating atomic layers. This yields a new type of magnetism in which strong and weak magnetism co-exist. Furthermore, the researchers varied the composition of the material by means of substitution. That enabled them to adjust the working temperature and to strengthen the desired magnetocaloric properties. The materials used are widely available and suitable for mass production. That provides opportunities for the cheap production of high-performance devices for cooling or energy conversion.
Contact
For further information please contact Prof. Ekkes Brück +31 (o)15 278 31 58.
Reference
Advanced Energy Materials; Volume 1, Issue 6, pages 1215–1219, November 2011.