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nanotimes News in Brief Sensors //

A new Type of Magnetoelectric Sensor © Based on Material by Kiel University, Germany

12-04 :: April/May 2012

R

esearch teams at Kiel University in Germany have jointly developed a new type of magneto-

electric sensor, which is intended to allow the use of this important technology in the future. As opposed to conventional magnetoelectric measuring tech- niques, the new sensors operate at normal condi- tions. Neither cooling nor external magnetic bias fields are required.

“Our composites with exchange biasing present an international milestone in the research of magneto- electric materials,” says Professor Eckhard Quandt, senior author of the study and spokesperson of the Collaborative Research Centre 855 Magnetoelectric Composites – Future Biomagnetic Interfaces (CRC 855).

“By eliminating the dependence on externally ap- plied magnetic bias fields, we have removed a signi- ficant obstacle for the medical application of ma- gnetoelectric sensors such as magnetocardiography and magnetoencephalography.” As the sensors do not affect one another due to their particular design, measuring arrays made up of hundreds of units are now conceivable. This would enable the production of flow maps of heart currents or brain waves. The new composites consist of a complex sequence of around a hundred layers of material, each of which

Cross-section of a new magnetoelectric composite sensor as scanned in an electron microscope: piezoelectric mate- rial (bottom half) and magnetostrictive material with inte- grated support layers (upper half). © Christiane Zamponi / Kiel University / Institute of Materials Science

is only a few nanometres thick. The magnetoelectric sensors contain both magnetostrictive and piezoelec- tric layers which, on the one hand, deform due to a