Indian-origin American researcher Jagdish (Jay) Narayan from North Carolina State University has developed novel multiferroic materials that will aid develop new electronic memory devices. Multiferroic materials have both ferroelectric and ferromagnetic properties.
“These multiferroic materials offer the possibility of switching a material’s magnetism with an electric field, or switching its electric polarity with a magnetic field – making them very attractive for use in next-generation, low-power, nonvolatile memory storage devices,” explained Narayan, John C. Fan Distinguished Chair professor of materials science and engineering.
“We have already fabricated prototype memory devices using these integrated, multiferroic materials and are testing them now,” Narayan, an IIT- Kanpur alumni, said.
Researchers had previously known that a multiferroic material can be created by layering barium titanate (BTO), which is ferroelectric and lanthanum strontium magnese oxide (LSMO), which is ferromagnetic.
Narayan’s team advanced the work in two ways. First, by developing a technique to give BTO ferromagnetic properties, making it multiferroic without the need for LSMO and second by developing buffer layers that can be used to integrate either the multiferroic BTO or the multiferroic BTO/LSMO bilayer film onto a silicon chip.
To make BTO multiferroic, the researchers used a high-power nanosecond pulse laser to create oxygen vacancy-related defects into the material.
These defects create ferromagnetic properties in the BTO. “We will now begin looking for industry partners to make the transition to manufacturing,” Narayan said.
Narayan had earlier invented domain matching epitaxy (DME), which is based upon matching of integral multiples of lattice planes across the film-substrate interface, which was licensed to Kopin (and Kobrite) Corp.
He is also known for his patents on integrated smart sensors and 3-D self-assembled nanostructures with oriented magnetic nanodots formed by the DME paradigm for information storage which NSF hailed as one of the breakthroughs of the year 2004 (US Patent # 7,105,118).
Narayan’s work on bulk nanocrysatlline materials started nanotechnology revolution in metal-ceramic nanocomposites. His most recent work on inverse Hall-Petch and grain softening, and twinning deformation in nanocrystalline materials has been highly cited and has laid the foundation for nanostructure and property correlations in nanoscale bulk materials.
Narayan also pioneered the concept of solute trapping in semiconductors by his discoveries of laser annealing in the late seventies and the formation of supersaturated semiconductor alloys for which he received 1981 US-DOE Award and 1983 IR-100 on Supersaturated Semiconductor Alloys that form the backbone of modern Integrated Circuits.
He received the 2011 Acta Materialia Gold Medal for these pioneering contributions and his leadership in materials science worldwide. The concept of solute trapping, which was introduced by John Cahn in the early seventies, resulted in the 2011 Kyoto Prize for Cahn and the 2011 Nobel Prize for Dan Shechtman for his work on quasicrystals which formed due to Mn solute trapping in aluminum-manganese alloys.