Magnetism has been used to store information in the last century. Audio tapes and hard drives exploit the fact that magnets have a north- and south pole. Even for more modern magnetic memories, like MRAM (magnetic random access memory), the direction of the magnetization vector determines the ones and zeros in the device.
One of the advantages of magnetic memories is that the information is maintained, even if the device is off. However, switching the magnetization comes with a significant energy cost. On HDD hard drives and audio tapes, this switching is done by bringing a strong magnet close and thus forcing a re-polarization of the bit. In MRAM devices, the switching happens with the application of currents through the devices, already improving energy efficiency.
The promising material: Bismuth Ferrite
Researchers recently discovered materials where the electrical and magnetic properties are so intimately linked, that the application of a voltage is enough to change the magnetic structure.
One of the examples is Bismuth Ferrite, a so-called multiferroic material. In this material, the magnetic texture is complex, as the spins are arranged in wavy patterns, so-called spin-cycloids. A team from UC Berkeley and Northeastern University used Qnami ProteusQ to image these spin-cycloids. They observed, how the spin-cycloids deterministically flipped their direction after the application of a voltage between two electrodes.
This discovery brings the development of ultra-efficient spintronic devices one step closer to reality. Check out the paper in Nature Communications.
The role of ProteusQ
Dr. Peter Meisenheimer, first author and leading scientist of the work shared with us his vision about the crucial role of Scanning NV Magnetometry in the field and how ProteusQ made it possible to achieve these groundbrealking results:
It seems like NV magnetometry will soon become as widespread and useful as tried-and-true scanning probe techniques like PFM and cAFM. Not only can we design experiments around the ProteusQ to take advantage of its functionality, it can also slot seamlessly into existing characterization as a standard measurement to give us an astonishing level of detail on functional materials. We have been able to generate an enormous amount of textbook quality data in a short amount of time because of how easy the system is to work into our existing projects.
We congratulate Dr. Peter Meisenheimer and Prof Ramamoorthy Ramesh from UC Berkeley, their colleague Prof. Paul Stevenson from Northeastern University, and the rest of the collaboration from Rice University, Brown University, and the Lawrence Berkeley National Laboratory, for their important work that will pave the way for ultraefficient spintronic devices.
What about you?
Are you also working with contemporary nanomagnetic materials such as BFO? The magnetic stray fields they generate are so small and decay so quickly with distance that the relevant structure can often be resolved only if the sensor is ultimately closed. With ProteusQ and the Quantilever MX tips, you get as close as possible to the source allowing for ultrasensitive imaging.
Qnami ProteusQ
ProteusQ is a complete quantum microscope system. It is the first scanning NV (nitrogen-vacancy) microscope for the analysis of magnetic materials at the nanoscale. The system allows user to detect extremely small magnetic fields generated from a wide range of materials, even antiferromagnets.
What about exploring how ProteusQ can help you prove your hypotheses and push the frontiers of science? If you are curious, then contact our Sales Managers, Dr. Joerg Lenz (sales@qnami.ch).
Will your application be the next one?
Scanning NV Magnetometry is unlocking more and more applications in the field of nanoscale magnetism. Can yours be the next one? Let’s find out together. Drop an email to our Application Scientist Dr. Peter Rickhaus (AppLab@qnami.ch).
We would be happy to talk with you. Share with us the challenges you face when it comes to measure magnetic properties of your sample. We might be able to help you. Would you like to discuss with us about your application? Let’s have a chat.