Scientists at the U.S. Department of Energy’s (DOE) Argonne National
Laboratory have developed a new technique that maps the magnetic vector potential
— one of the most important electromagnetic quantities and a foundation
of quantum mechanics — in three dimensions. Funding for the research,
including the TEM situated in the Materials Science Division, was provided by
the U.S. Department of Energy's Office of Science. The patterned structures
were prepared at the Center for Nanoscale Materials with Alexandra Imre.
"The vector potential of magnetic structures is essential to the understanding
of several areas in condensed matter physics and magnetism on a quantum level,
but until now it has never been visualized in three dimensions,” Argonne
Distinguished Fellow Amanda Petford-Long said. “If you want to understand
the way magnetic nanostructures behave, then you have to understand the magnetic
According to Petford-Long, research into the creation and manipulation of magnetic
nanostructures will enable the development of the next generation of data storage
in the form of magnetic random access memory.
Petford-Long and post-doctoral researcher Charudatta Phatak used a transmission
electron microscope (TEM) to examine a series of different nanostructures. The
theoretical and numerical reconstruction procedure was developed in collaboration
with Prof. Marc De Graef at Carnegie Mellon University.
Using the TEM, the researchers were able to take images from several different
angles and then rotate the structure by 90 degrees until they had several series
of images. The scientists then extracted the vector potential by reconstructing
how the electrons in the material shifted phase.
“The development of next generation magnetic sensors and devices requires
studying the physics underlying the magnetic interactions at the nanoscale,”
Phatak said. “This 3-D map is the first step to truly understanding those
A paper on this research has been published in the June 25 issue of Physical
Review Letters (Vol. 104, No. 25).
Funding for the research, including the TEM situated in the Materials Science
Division, was provided by the U.S. Department of Energy’s Office of Science.
The patterned structures were prepared at the Center for Nanoscale Materials
with Alexandra Imre.
The Center for Nanoscale Materials at Argonne National Laboratory is one of
the five DOE Nanoscale Science Research Centers (NSRCs), premier national user
facilities for interdisciplinary research at the nanoscale, supported by the
DOE Office of Science. For more information about the DOE NSRCs, please visit