Magnetoelectronics

CNSE Magnetoelectronics Team (CMET)

The goal of the CNSE Magnetoelectronics Team is to develop new materials and processes for low-cost, disposable components that will function as magnetic shielding, magnetism sensors and memory storage in future Flexible Microelectronics devices. The team is focusing on polymeric-based magnetic formulations given the ability to process such materials in a roll-to-roll manufacturing environment. The CMET works closely with CNSE electronics technology engineers in the development of wireless magnetic sensors. In addition, the CMET provides program management and technical leadership for the NSF-supported NDSU Organic Spintronics program where tenure-track faculty from Chemistry, Civil Engineering, Mechanical Engineering, and Coatings and Polymeric Materials partner in all aspects of this research from new materials to device fabrication to characterization.

Spintronics is an extension of traditional electronics that uses spin in addition to charge to create additional functionality. This added functionality will allow the development of next generation technologies. For example, computers with spintronics memory will not require a constant energy source so they consume much less energy and are instantly on. In addition, spintronic magnetic sensors will offer ultrahigh sensitivities enabling the sensing of very small electrical pulses in the brain (i.e., magnetoencephalography).

The push of NDSU in the field of spintronics is to use organic-based materials to fabricate the magnetic components required to produce spin. The science advantage of organic materials includes creating more abrupt interfaces and improved transport properties of the spin carrying charges. The political and economic advantage of organic based spintronics is the low cost of raw materials and processing and the hope that an organic basis is more compatible with low-pollution processing. 

One possible outcome of these efforts may be the revolution of tape-based magnetoelectronics through the rational design of new organic-based heterostructured devices. This new effort builds on a foundation of basic and applied science where both experimental and theoretical understanding of the relationships between structure and the magnetic and electronic properties of organic materials will yield new high-tech processes that are amenable to roll-to-roll manufacture. The project will seed the future by both (1) developing new technology that will have an impact on the ND high-technology manufacturing base and (2) training graduate students that will become the basis for a skilled entry-level workforce that can operate the new manufacturing plants. Toward that end, the results of our research and development activities are disseminated in peer reviewed journals after appropriate consideration of the intellectually property upside potential. Both peer-reviewed journal articles and the IP generated by this group provides a path toward American Competitiveness in a field (i.e., high-technology manufacturing) that has been deemed critical to the future success of our national economy.

Technical Detail

Investigation of magnetic nanostructures has become a frontier of condensed matter physics and material science due to the highly visible commercial success of the recording and memory devices (i.e., in 2006 hard drives market approached ~$5 billion). Spintronics is a subset of magnetoelectronics where devices utilize the magnetic moment or spin of electron in addition to its charge. The modern spintronics-based read head consists of alternate layers (about one nm thick) of magnetic and non-magnetic metals or alloys whose resistance depends upon a relative orientation of magnetic moments in the adjacent magnetic layers. Its implementation enabled a million-fold increase in hard drive capacity during the last decade. Recently, the first commercial spintronic-based non-volatile magnetic random access memory (MRAM) device entered the market (i.e., Freescale’s 4 MB MRAM, which now sells for $25 USD). However, to achieve a suitable sensitivity up to 100 such layers have to be deposited using sophisticated and expensive UHV systems, which considerably increases the device cost. In addition, MRAM uses a large data writing current (~5 mA), which creates problems with power consumption and device scaling.

Organic-based magnets represent a paradigm shift in the way spintronics devices are constructed and operated. Specifically, organic-based materials generally demonstrate low differences in free energy between the surface and bulk, are rich of light elements leading to reduced spin-orbit scattering and/or hyperfine interaction, and offer wide flexibility in tuning their electronic structure; such properties allow for interface stability and elastic electron spin transport. Organic thin-film technology does not require high temperatures and lattice matching as in the case of inorganic heterostructures, making their fabrication cost efficient.