Material can be magnetically and electrically polarised

Researchers in Copenhagen have discovered a new material that could open up possibilities for sensors of the future.

A team from Niels Bohr Institute at Copenhagen University says it has found a material that can be both magnetically and electrically polarised — a rare phenomenon that is only now being understood thanks to modern analysis technology.

More research is needed to determine how this ‘multiferroic’ material could be used, but other work has focused on highly sensitive magnetic field sensors and electrically tunable microwave devices.

The researchers were aiming to get a general understanding of the terbium-iron compound and a more precise image of the relationship between the structure of the material and its physical properties.

‘We have studied the rare, naturally occurring iron compound, TbFeO3, using powerful neutron radiation in a magnetic field,’ said Kim Lefmann, associate professor at Copenhagen University’s Nanoscience Center, in a statement.

The interaction between the transition metal, iron, and the rare element, terbium, plays an important role in the magneto-electrical material.

The terbium’s waves of spin cause a significant increase in the electric polarisation and the interaction between the ions of the elements creates one of the strongest magneto-electrical effects observed in materials.

‘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,’ said Lefmann.

‘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.’

The experiments were conducted at the Helmholtz-Zentrum neutron research facility in Berlin in collaboration with researchers in Holland, Germany, at ESS in Lund and at Risø/DTU.

The researchers’ work has been published in the journal Nature Materials.