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Rensselaer Polytechnic Institute (RPI)

New Hybrid Nanostructures Detect Nanoscale Magnetism

December 8, 2008

New Hybrid Nanostructures Detect Nanoscale Magnetism

A scanning electron micrograph of cobalt nanoclusters embedded in multi-walled carbon nanotubes. Researchers at Rensselaer used these new hybrid structures, the first of their kind, to detect magnetism at the nanoscale.
Photo Credit: Saikat Talapatra/Caterina Soldano

Research could pave way for new data storage devices, drug delivery systems

A key challenge of nanotechnology research is investigating how different materials behave at lengths of merely one-billionth of a meter. When shrunk to such tiny sizes, many everyday materials exhibit interesting and potentially beneficial new properties.

Magnetic behavior is one such phenomenon that can change significantly depending on the size of the material. However, the sheer challenge of observing the magnetic properties of nanoscale material has impeded further study of the topic.

Researchers at Rensselaer Polytechnic Institute have developed and demonstrated a new method for detecting the magnetic behaviors of nanomaterials. They created a new process for creating a single multi-walled carbon nanotube that is embedded with cobalt nanostructures. The cobalt clusters measure from 1 nanometer to 10 nanometers. 

After a series of experiments, the research team has concluded that the electrical conductance of carbon nanotubes is sensitive enough to detect and be affected by trace amounts of magnetic activity, such as those present in the embedded cobalt nanostructures. It is believed to be the first instance of demonstrating the detection of magnetic fields of such small magnets using an individual carbon nanotube.

Results of the study were reported in the paper “Detection of Nanoscale Magnetic Activity Using a Single Carbon Nanotube” recently published by Nano Letters

“Since the cobalt clusters in our system are embedded inside the nanotube rather than on the surface, they do not cause electron scattering and thus do not seem to impact the attractive conductive properties of the host carbon nanotube,” said Swastik Kar, research assistant professor in Rensselaer’s Department of Physics, Applied Physics, & Astronomy, who led the project. “From a fundamental point of view, these hybrid nanostructures belong to a new class of magnetic materials.” 

“These novel hybrid nanostructures open up new avenues of research in fundamental and applied physics, and pave the way for increased functionality in carbon nanotube electronics utilizing the magnetic degree of freedom that could give rise to important spintronics applications,” said Saroj Nayak, an associate professor in Rensselaer’s Department of Department of Physics, Applied Physics, and Astronomy, who also contributed to the project. 

Potential applications for such a material include new generations of nanoscale conductance sensors, along with new advances in digital storage devices, spintronics, and selective drug delivery components.

Co-authors of the paper include Caterina Soldano, formerly a graduate student at Rensselaer who is now a postdoctoral research associate at the Centre d’Elaboration de Matériaux et d’Etudes Structurales in Tolouse, France; Professor Saikat Talapatra of the Physics Department of Southern Illinois University, Carbondale; and Prof. P.M. Ajayan of the Rice University Department of Mechanical Engineering and Materials Science.

Researchers received funding for the project from the New York State Interconnect Focus Center at Rensselaer.

Contact: Michael Mullaney
Phone: (518) 276-6161
E-mail: mullam@rpi.edu

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About Rensselaer Polytechnic Institute

Founded in 1824, Rensselaer Polytechnic Institute is America’s first technological research university. Rensselaer encompasses five schools, 32 research centers, more than 145 academic programs, and a dynamic community made up of more than 7,900 students and more than 100,000 living alumni. Rensselaer faculty and alumni include more than 145 National Academy members, six members of the National Inventors Hall of Fame, six National Medal of Technology winners, five National Medal of Science winners, and a Nobel Prize winner in Physics. With nearly 200 years of experience advancing scientific and technological knowledge, Rensselaer remains focused on addressing global challenges with a spirit of ingenuity and collaboration.