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 Using a simple, scalable method, a material that can be used as a sensor is developed
15.02.2017 | University of the Basque Country

nachricht New mechanical metamaterials can block symmetry of motion, findings suggest
14.02.2017 | University of Texas at Austin

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Biocompatible 3-D tracking system has potential to improve robot-assisted surgery

17.02.2017 | Medical Engineering

Real-time MRI analysis powered by supercomputers

17.02.2017 | Medical Engineering

Antibiotic effective against drug-resistant bacteria in pediatric skin infections

17.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>