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Significance Statement
Modern electronics directly depend on the novel materials, allowing for better and faster performance. In parallel, densely integrated circuits generate electromagnetic radiation that can harm sensitive electronics and living beings. Despite great efforts, controllable microwave absorption that would extend over a wide microwave region, allowing for improved electromagnetic shielding and superior signal processing, is still missing.
Here we highlight a new functionality of layered metamagnets, namely, their ability to absorb electromagnetic radiation in an extremely wide frequency range. The effect is controllable by the external magnetic field, which actuates the absorbing mixed ferro/antiferromagnetic phase that is stabilized by a finite demagnetization field. This is demonstrates in Cu3Bi(SeO3)2O2Br compound, where the controllable absorption extends over almost ten decades in frequency.
As the required strength of the controlling magnetic field is in artificial metamagnets, i.e., magnetic multilayers, easily adjusted, a direct tuning of the essential functional properties of these materials is imminent.
Journal Reference
Advanced Functional Materials, Volume 25, Issue 24, pages 3634–3640, June 24, 2015.
Matej Pregelj1,*, Oksana Zaharko2, Andrej Zorko1, Matjaž Gomilšek1, Oles Sendetskyi2, Axel Günther3, Mykhaylo Ozerov4, Sergei A. Zvyagin4, Hubertus Luetkens2, Christopher Baines2, Vladimir Tsurkan3,5 , Alois Loidl3
[expand title=”Show Affiliations”]- Jožef Stefan Institute, Ljubljana, Slovenia.
- Laboratory for Neutron Scattering and Laboratory for Micro- und Nanotechnology and Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut, Villigen, Switzerland.
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, Augsburg, Germany.
- Dresden High Magnetic Field Laboratory (HLD), Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.
- Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau, Republic of Moldova
Abstract
Materials with broad absorption bands are highly desirable for electromagnetic filtering and processing applications, especially if the absorption can be externally controlled. Here, a new class of broadband-absorption materials is introduced. Namely, layered metamagnets exhibit an electromagnetic excitation continuum in the magnetic-field-induced mixed ferro- and antiferromagnetic phase. Employing a series of complementary experimental techniques involving neutron scattering, muon spin relaxation, specific heat, ac and dc magnetization measurements, and electron magnetic resonance, a detailed magnetic phase diagram of Cu3Bi(SeO3)2O2Br is determined and it is found that the excitations in the mixed phase extend over at least ten decades of frequency. The results, which reveal a new dynamical aspect of the mixed phase in metamagnets, open up a novel approach to controllable microwave filtering.
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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