Yunlong Jin

Spinodal Nanodecomposition in Semiconductors Doped with Transition Metals
Advisor: Dr. David J. Sellmyer

In recent years, there has been an upsurge of the research on nanostructuring to create new materials with desired properties. Spinodal nanodecomposition is one method that is potentially capable of producing magnetic ordering of semiconductors above room temperature. The theories for understanding spinodal nanodecomposition and recent progress in spinodal nanodecomposition in high-temperature magnetic semiconductors, such as (Ga, Mn)As and (Ga, Mn)N, are reviewed in the first part. The nanostructures of the separated two phases can be controlled via proper experimental conditions. Magnetic properties and related mechanisms are discussed. Spintronics applications with magnetic semiconductors are also illustrated. Finally, I propose a potential new permanent magnet Co-Fe-Cr-Ge alloy system with three phases formed via spinodal decomposition methods together with multi-steps heat treatments to enhance magnetic properties, and bottom-up spinodal decomposition technology of synthesizing alnico and Co-Fe-Cr-Ge thin film with ?-(Fe, Co) phase nanocolumns. A possible gas-aggregation-type cluster-deposition method to grow magnetic semiconductors is also discussed.