News, Science & Research

Physicists refine analysis of nano-objects

Researchers find that manipulating NMR coils enhances ability to study small objects

By
Science and Research Editor
Wednesday, January 24, 2018

While nuclear magnetic resonance technology has long been used in physics to study materials, it has not been especially effective at analyzing small, thin substances. New research from University scientists published in the Review of Scientific Instruments unveils how the orientation of coils matters and can drastically increase the quality of results obtained by NMR analysis.

NMR technology works by placing an object inside of a cylindrical coil to bombard the object with radio waves, causing nuclei within the object to give off signals that offer scientists information about its composition. Because the coils use particles of the object for analysis, objects with a large number of particles have better readings, meaning that small, flat nanomaterials are extremely difficult to analyze under the traditional coils. The researchers found that using flat coils instead of cylindrical coils creates more accurate readings of these objects, expanding the scope of what can be analyzed with NMR technology, said Wencong Liu PhD’17, co-lead author of the study.

The research was born out of the issues associated with the previous NMR technique, said Vesna Mitrovic, associate professor of physics and co-lead author of the study. Because different geometries of the coil allow enhanced readings of these objects, the paper investigated optimal geometries for particular objects. Scientists are now better able to determine the properties of these small objects, which is extremely useful in a large number of areas, such as in making electronic devices, Mitrovic said.

This solved a prominent issue within NMR technology, said Kemp Plumb, assistant professor of physics. Because scientists previously used round coils in their experiment, they had difficulty studying square objects, since it resulted in an overabundance of empty space. The same kind of excess space existed when NMR is used to study small objects, rendering the technique ineffective.

These findings could contribute to Plumb’s area of research, which is the study of magnetism and “exotic” materials, or materials that have uncommon properties. Plumb’s work specifically focuses on the atomic-level activity that gives rise to the macroscopic aspects of an object. One example is superconducting material, or material that conducts electricity similarly to metal but is unique in that it has no resistance. The properties of the superconductor are only possible due to the activity of its electrons. NMR technology will allow him to study substances on a microscopic level to aid understanding of how these kinds of characteristics arise.

This finding also broadly expands the scope of what NMR technology can do in scientific research. The new method allows the materials being analyzed to be manipulated in a number of ways, such as applying stress or voltage, Liu said. This was not possible beforehand, as the previous method involved enclosing the object.

Correction: An earlier version of this article stated that electrons within an object give off signals during Nuclear Magnetic Resonance analysis. In fact, nuclei within an object give off signals during Nuclear Magnetic Resonance analysis. The Herald regrets the error.