The "8-armed candlestick" in this unusual image of the
measurements is proof that the "walls" of the domains in TbFeO3 repel
each other at certain temperatures and therefore lie at a fixed distance
from each other. The signal from the "ordinary" chaotic domain walls
would more resemble a fly swatter. Credit: Niels Bohr Institute
Normally a material can be either magnetically or
electrically polarized, but not both. Now researchers at the Niels Bohr
Institute at the University of Copenhagen have studied a material that
is simultaneously magnetically and electrically polarizable. This opens
up new possibilities, for example, for sensors in technology of the
future. The results have been published in the scientific journal, Nature Materials.
Materials that can be both magnetically and electrically polarized
and also have additional properties are called multiferroics and were
previously discovered by Russian researchers in the 1960s. But the
technology to examine the materials did not exist at that time. It is
only now, in recent years, that researchers have once again focused on
analyzing the properties of such materials. Now you have research
facilities that can analyze the materials down to the atomic level.Surprising test results
"We have studied the rare, naturally occurring iron compound, TbFeO3, using powerful neutron radiation in a magnetic field. The temperature was cooled down to near absolute zero, minus 271 C. We were able to identify that the atoms in the material are arranged in a congruent lattice structure consisting of rows of the heavy metal terbium separated by iron and oxygen atoms. Such lattices are well known, but their magnetic domains are new. Normally, the magnetic domains lie a bit helter-skelter, but here we observed that they lay straight as an arrow with the same distance between them. We were completely stunned when we saw it," explains Kim Lefmann, Associate Professor at the Nano-Science Center, University of Copenhagen.
