Research News
HZB scientist Florin Radu inspects a BaTiO3 sample by means of the ALICE diffractometer. Photo: Helmholtz-Zentrum Berlin
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The scientist now published their results in Nature Materials in an article under the heading "Interface-induced room-temperature multiferroicity in BaTiO3".
New Material for Fast Data Storage Developed
Scientists from the Helmholtz-Zentrum Berlin (HZB), in cooperation with colleagues from France and the United Kingdom, have developed a material displaying both ferroelectric and ferromagnetic characteristics at room temperature, thus making it "multiferroic". For this reason, an electric field can also indirectly influence the magnetisation.
The scientists around Dr Sergio Valencia worked with an extremely thin layer of barium titanate, which at room temperature is ferroelectric but not ferromagnetic. They induced ferromagnetism by applying only a few layers of ferromagnetic iron and cobalt atoms on a barium titanate layer. At the Berlin electron storage ring BESSY II, they then used the method of "Soft X-Ray Resonant Magnetic Scattering" to investigate the magnetic momentum of the titanium and oxygen atoms in the barium titanate. "We were able to show that multiferroic characteristics are possible at room temperature", says Valencia. Other hitherto known multiferroic substances display this exotic characteristic only at temperatures way below freezing point, so that elaborate cooling would be required in utilising the effect in technical applications. Conversely, the phenomenon is extremely rare at room temperature but all the more interesting for potential applications: The magnetisation of the barium titanate can be influenced by applying external voltage and thus reversing the material's polarisation. A data storage device based on this material thus could be written on by connecting it with an electric field. According to Valencia, this is much cheaper than the traditional use of magnetic fields.
