An international team of researchers from France and Germany has developed a new material which is the first to react magnetically to electrical fields at room temperature. Previously this was only at all possible at extremely low and unpractical temperatures. Electric fields are technically much easier and cheaper to produce than magnetic fields for which you need power guzzling coils.
The researchers have now found a way to control magnetism using electric fields at “normal” temperatures, thus fulfilling a dream. The high-precision experiments were made possible in a highly specialized measuring chamber built by the Ruhr-Universität Bochum at the Helmholtz Centre in Berlin. The research group from Paris and Berlin with the participation of RUB scientists reported on their findings in “Nature Materials”.
ALICE in wonderland
The “multiferroic” property of the new material was demonstrated in the measuring chamber ALICE – so called because, like “Alice in wonderland” it can look beneath the surface of things. Here a specific range of X-rays is used to study magnetic nanostructures. The measuring chamber, developed by Bochum’s physicists and funded by the Federal Ministry for Education and Research, has successfully been in use since 2007 at the electron storage ring BESSY II in Berlin. With the newly discovered material properties of BaTiO3 (bismuth-titanium oxide), in future it will be possible to design components such as data storage and logical switches that are controlled with electric instead of magnetic fields.
Ferromagnetic and ferroelectric properties
Ferromagnetic materials such as iron can be affected by magnetic fields. All atomic magnetic dipoles are aligned in the magnetic field. In ferroelectric materials, electric dipoles - two separate and opposite charges - replace the magnetic dipoles, so they can be aligned in an electric field. In very rare cases, so-called multiferroic materials respond to both fields - magnetic and electric.
Multiferroic at room temperature
The researchers produced this multiferroic material by vapour coating ultra-thin ferromagnetic iron layers onto ferroelectric bismuth-titanium oxide layers. In so doing, they were able to establish that the otherwise non-magnetic ferroelectric material becomes ferromagnetic at the interface between the two ferromagnetic layers. Thus, the researchers have developed the world’s first multiferroic material that reacts to both magnetic and electric fields at room temperature.
Magnetic X-ray scattering throws light on new control mechanism
The scientists demonstrated this interfacial magnetism using the spectroscopic method “X-ray magnetic circular dichroism”. In this method, the polarisation of the X-rays is affected by magnetism – in a way which is similar to the famous “Faraday effect” in optics. X-ray magnetic circular dichroism has the advantage that it can be applied to every single element in the material investigated. With this method, the researchers were able to show that all three elements in the ferroelectric material - bismuth, oxygen and titanium - react ferromagnetically at the interface to iron, although these atoms are otherwise not magnetic.
An extremely sophisticated method
“The method of X-ray magnetic circular dichroism is highly complex”, said Prof. Dr. Hartmut Zabel, Chair of Experimental Physics at the RUB. The measuring chamber ALICE combines X-ray scattering with X-ray spectroscopy. “This is an extremely sophisticated and very sensitive method”, explained Prof. Zabel. “The high precision of the detectors and all the goniometers in the chamber led to the success of the experiments conducted by the international measuring team.”
S. Valencia et al.: “Interface-induced room-temperature multiferroicity in BaTiO3”. Nature Materials, DOI: 10.1038/NMAT3098
Prof. Dr. Hartmut Zabel, Chair of Experimental Physics / Solid State Physics at the Ruhr-Universität Bochum, tel. +49 234 32 23649, e-mail: firstname.lastname@example.org
Editor: Jens Wylkop
Dr. Josef König | idw
Spider silk key to new bone-fixing composite
20.04.2018 | University of Connecticut
Diamond-like carbon is formed differently to what was believed -- machine learning enables development of new model
19.04.2018 | Aalto University
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy