Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Magnetism at Nanoscale

04.08.2015

Ames Laboratory physicists using N-V center optical magnetoscope to understand new magnetic nanomaterials

As the demand grows for ever smaller, smarter electronics, so does the demand for understanding materials’ behavior at ever smaller scales. Physicists at the U.S. Department of Energy’s Ames Laboratory are building a unique optical magnetometer to probe magnetism at the nano- and mesoscale.


U.S. Department of Energy's Ames Laboratory

Physicists at the U.S. Department of Energy's Ames Laboratory are using an NV-magnetoscope to make use of nitrogen-vacancy centers in diamond to sense extremely weak magnetic fields in nano- and mesoscale magnetic materials.

The device, called a NV-magnetoscope, makes use of the unique quantum mechanical properties of nitrogen-vacancy (NV) centers in diamond. The low temperature NV-magnetoscope setup incorporates a confocal microscope (CFM) and an atomic-force scanning microscope (AFM). The NV-magnetoscope will be able to sense the extremely weak magnetic fields of just a handful of electrons with the spatial resolution of about 10 nanometers.

“We want to determine magnetic textures more precisely than ever before, at smaller scales than ever before,” said Ames Laboratory physicist Ruslan Prozorov. “Our hope is to understand nano- and mesoscale magnetism, learn how to control it and, eventually, use that to create a new generation of technologies.”

NV Centers

Usually, diamonds are most valued when they’re perfect and big. But physicists see special value in diamonds’ tiny flaws: a certain kind of imperfection, called a nitrogen vacancy (NV) center, serves as a very sensitive sensor of the magnetic field exactly at the location of the NV center. NV centers are created when a carbon atom is substituted with a nitrogen atom. When there is a missing atom or a “vacancy” nearby the nitrogen atom, this forms the stable pair called the nitrogen-vacancy center.

What makes NV centers so useful? Physicists know a lot about how NV centers work. (In fact, Ames Laboratory is home to one of the world’s leading experts on NV centers, theoretical physicist Viatcheslav Dobrovitski.) Scientists know how much energy it takes to push electrons from the lowest energy, or ground state, to an excited state and, more importantly, how much energy will be released in form of a red photon when the electron relaxes back to the low-energy level. NV centers’ well-defined quantum energy levels are extremely sensitive to a magnetic field. This sensitivity enables the NV-magnetoscope to detect very small magnetic fields – such as that produced by nano- and mesoscale magnetic materials, for example – by reading optical fluorescence emitted by the excited NV centers.

Green Laser Light Excites the NV Center

“Electrons start at low-energy quantum states. And the green laser light ‘kicks’ them to a high excited state. The rules of quantum mechanics say that those electrons must return back to the lower energy level. If an electron was excited from a non-magnetic level, it always emits red light. However, if it was excited from one of the low-energy magnetic levels, it most likely relaxes back without any emission.

Microwave radiation is used to scramble electrons between low-energy magnetic and non-magnetic states, reaching maximum population of the magnetic states when the interlevel energy difference matches microwave energy. Therefore, by scanning microwave frequency, red fluorescence will cause double-dip spectra, corresponding to two magnetic energy levels, split by the magnetic field (called Zeeman splitting). The distance between the dips is proportional to the magnetic field at the location of an NV center,” said Prozorov

Detector Counts Red Photons

As excited electrons lose energy and return back to the low energy state, they emit red light. A detector counts the number of red photons.

NV Centers “Feel” Sample’s Magnetic Fields

A roughly 100-nanometer-long diamond containing NV centers is attached to the AFM tip. The confocal microscope focuses on a single NV center, collecting red photons only from one tiny area while blocking out outside “noise.” The sample of interest is scanned below the NV center. The NV center “feels” the variation of magnetic fields produced by the sample.

“When the sample of interest is brought close enough to an NV center, the sample’s magnetic field is extended to the location of the NV center and affects the center’s quantum energy levels. By accurately moving the sample in two dimensions close to the NV center, we can reconstruct the magnetic field intensity map produced by the sample. This, in turn, gives access to the magnetic properties of the sample itself,” said Prozorov.

This work was supported by the DOE Office of Science.

Ames Laboratory is a U.S. Department of Energy Office of Science national laboratory operated by Iowa State University. Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaborations to solve global problems.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

Contact Information
Breehan Gerleman Lucchesi
Communications specialist
breehan@ameslab.gov
Phone: 515-294-9750

Breehan Gerleman Lucchesi | newswise
Further information:
http://www.ameslab.gov

More articles from Materials Sciences:

nachricht New gel-like coating beefs up the performance of lithium-sulfur batteries
22.03.2017 | Yale University

nachricht Pulverizing electronic waste is green, clean -- and cold
22.03.2017 | Rice University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>