Student's innovations may improve data storage, magnetic sensors

Washington, May 15 : A student of Rensselaer Polytechnic Institute has come up with two innovations that may vastly improve magnetic data storage, and sense extremely low level magnetic fields in everything from ink on counterfeit currency to tissue in the human brain and heart.

Paul Morrow first developed a nanomaterial by arranging alternating layers of magnetic cobalt and non-magnetic copper in such a way that it led to a three-dimensional structure.

His three-dimensional arrangement of the magnetic and non-magnetic layers creates a material that exhibits promising magnetic properties for data storage and magnetic field sensing at room temperature.

Although a similar technology is currently in use in hard drives, they use a two-dimensional film design for the layers.

"Because the nanostructure is three-dimensional, it has the potential to vastly expand data storage capability. A disk with increased data storage density would reduce the size, cost, and power consumption of any electronic device that uses a magnetic hard drive, and a read head sensor based on a small number of these nanocolumns has promise for increasing spatial sensitivity, so that bits that are more closely spaced on the disk can be read. This same concept can be applied to other areas where magnetic sensors are used, such as industrial or medical applications," Morrow said.

He also unveiled a microscopic technique to measure the minute magnetic properties of his nanocolumns.

This is the first time that a method to sense the magnetic properties of freestanding nanostructures has been innovated by a researcher.

Murrow revealed that the technique uses a specialized scanning tunneling microscope (STM) that contains no internal magnetic parts.

Most present-day STMs have magnetic parts that make it impossible for them to operate reliably in an external magnetic field.

With his modified non-magnetic STM, Morrow was able to use an electromagnet to control the magnetic behaviour of his nanocolumns, and measure the magnetic properties of fewer than 10 nanocolumns at one time.

"To date it has been extremely difficult to get an instrument to detect magnetic properties on such a small scale. With this type of sensitivity, engineers will be able to sense the very low level magnetic properties of a material with sub-micron spatial resolution," Morrow said.

At present, he is trying to fine-tune the device to detect the properties of just one nanocolumn.

Murrow believes that his technique may turn out to be significant for the study of other magnetic nanostructures for magnetic sensing applications, such as motion sensors for industrial applications, detection of magnetic ink in currency and other secure documents.

He says that his technique may even help detect and further understand the minuscule magnetic fields generated by the human body.

Murrow's discoveries have been described in two research articles published in the journal Nanotechnology.

ANI