Rensselaer researchers have opened up new possibilities with a recent invention: nanoscopic magnetic sensors. Comprised of carbon nanotubes embedded with bundles of cobalt atoms, these magnetic field sensors are the first ever capable of reliably detecting magnetic fields at near atomic levels.
This discovery is being called “a new class of magnetic materials.” The nano-device’s cobalt clusters are embedded within the walls of a multi-layered carbon nanotube, just 1–10 nm in diameter. Since the clusters are internal to the tubes, rather than external, “they do not cause electron scattering, and thus do not seem to impact the attractive conductive properties of the host carbon nanotube,” according to Assistant Professor Swastik Kar, Department of physics, who led the project.
A series of experiments has shown that the cobalt-cluster carbon nanotubes are almost sensitive enough to detect the miniscule magnetic fields of atoms. The research team believes this is the first time such small magnetic fields have been reliably detected using carbon nanotubes, and it provides a new tool for analyzing the nanoscopic magnetic properties of many everyday item—something that was not possible previously due to an interference of the source materials used in the detector.
The results of this study were published in an article entitled “Detection of Nanoscale Magnetic Activity Using a Single Carbon Nanotube” in Nano Letters.
According to the research, potential future applications include “new generations of nanoscale conductance sensors, new advances in digital storage devices, spintronics, and selective drug delivery components.” Today’s most advanced perpendicular storage techniques allow up to around 200 gigabytes of data per square inch. Hard drives on the order of 10 nanometers per bit would allow upwards of 10 petabits per square inch. Perpendicular storage solutions are expected to reach a maximum around 1 terabit per square inch, though this ceiling appears to be constantly moving.
Today, semiconductors companies often utilize infrared emissions to detect electron movement through silicon-based transistors. The laser probes used in such labs detect the emission of infrared light, to which silicon is transparent, and which seeps through the back of the chip while the central processing unit is running.
By monitoring photon activity on the chip with the laser probe, the CPU debuggers can isolate individual circuits in operation. This helps them detect errors for chip designers and track down other problems or inefficiencies. This new RPI device may also produce an alternate method for detecting this kind of circuit activity.
Recent carbon nanotube-related research from Rensselaer includes a nanoscopic pressure sensor made of carbon nanotubes. RPI has also recently developed a solar cell coating that allows panels to absorb 90 percent of sunlight without the need for servos to track the sun’s movement.
