TEHRAN (INIC)- Iranian researchers managed to produce a new kind of nano-layers which are suitable for synthesis of magnetic field sensors to be used in large magnetic resistances.

The researchers could detect magnetic fields with magnitudes of less than 6 milliteslas (mT) by creating nanostructures of metals like platinum and copper on Si/SiO2/CuPt bases. Such a work is evaluated as a significant step forward in the production of magnetic field sensors with large magnetic resistances.

"In this work, a very thin film of silicon dioxide was deposited upon pure silicon, which was initially cleaned by a standard plasma cleaning process, by applying e-beam evaporation technique together with UV lithography," Seyedeh Maryam Banihashemian, a member of the research team, explained to the News Service of INIC.

The effort led to the deposition of a 5 nanometers thick layer upon the silicon bed. In addition, by controlling layer deposition rates and pressure, the scientists managed to obtain layers of copper-platinum upon silicon-silicon dioxide bases with thicknesses less than 8 nanometers.

Then, the samples underwent wire annealing and their current-voltage curves in presence of a variable magnetic field were studied.

The obtained curves indicated that the sensors were capable of detecting magnetic filed with magnitudes of even less than 6 milliteslas. Finally nano layers were characterized by AFM, SEM, RBS tests.

"It was observed that nanometric structure of Cu-Pt, when its size is decreased, could detect magnetic fields whose magnitudes differ form that of the earth in terms of several milliteslas," Banihashemian added.

"Also, by applying magnetic fields, they exhibit unique characteristics like large magnetoresistances. These nanostructures can be used in magnetic field sensors, magnetic memories and biosensors." she added.

More detailed information on this research work is available at the Journal of Magnetism and Magnetic Materials, volume 321, pages 2733 to 2736, 2009.