New clever composite material discovered
A clever new composite material can be given highly robust magnetic properties by heating and cooling it in a strong magnetic field of more than 20 Tesla. The discovery was made by scientist from the Max-Planck-Institute for Chemical Physics of Solids in Dresden who performed experiments at the HFML. Their work will be published in Nature
Materials on 16 March 2015.
Heating then cooling a compound made of manganese, platinum and gallium in a strong magnetic field produces a new magnetic material that retains an internal magnetisation of three Tesla, even when the external magnetic field is removed. Never before has such a large exchange bias been observed.
Promising material
HFML is a laboratory jointly operated by Radboud University and the Foundation for Fundamental Research on Matter. According to Uli Zeitler, researcher at the HFML, who worked together with the Dresden reseachers, the discovery is relevant because the properties of the newly-discovered effect can have many applications. Furthermore, the elements used are not rare, costly or poisonous, which is often the case with complex magnetic materials. "We are always looking for new, useful materials that can be used in innovative products. Take graphene for example: if we manage to make touchscreens from graphene we can replace the indium tin oxide in the screens with cheap, safe carbon. Tin is poisonous and extracted under difficult conditions."
European partnership
The paper in Nature Materials is the first publication since the European Magnet Field Laboratory (EMFL) was officially opened at the end of January this year. It immediately proves the benefits of such a partnership. Chemists at the Max-Planck-Institut für Chemische Physik fester Stoffe in Dresden invented and produced an interesting, ferri-magnetic material made from manganese, platinum and gallium. They first took the material to their neighbours, the Hochfeld-Magnetlabor Dresden (HLD-EMFL) at the Helmholtz-Zentrum Dresden-Rossendorf. The HLD is specialised in producing and taking measurements in extremely high magnetic field pulses (up to 100 Tesla for several milliseconds). It quickly became clear that the new material had some interesting properties but that it needed to spend longer in the magnetic field if these properties were to be further investigated and manipulated.
Continuous high field in Nijmegen
As the HLD is part of the EMFL, it was a logical next step to approach the HFML in Nijmegen, where strong magnetic fields can be produced for a longer time (up to several hours). It is also possible to vary conditions in the magnet in Nijmegen – in this case the temperature. Thanks to a combination of advanced synthesis and measurements in both pulsed and constant magnetic fields, the successful discovery and examination of a spectacular new magnetic material was finally made possible.
More information
Design of compensated ferrimagnetic Heusler alloys for giant tunable exchange bias
Ajaya K. Nayak e.a
Nature Materials DATUM DOI: 10.1038/NMAT4248
u.zeitler@science.ru.nl
+31 (0)24 365 30 61