The theme of this project is to understand and manipulate spins and magnetismin self-assembled nanoparticle arrays with potential for spintronic and high frequency applications. Theresearch approach includes material synthesis, self-assembly, property characterization, device fabrication, and theoretical modeling to address fundamental challenges impeding progressin nanomagnetism and spintronics. Research efforts are grouped into three topics: 1) development ofnanoscale building blocks based on solution phase synthesis, with emphasis on half-metallicnanoparticles, diluted magnetic semiconductor (DMS) quantum dots (QDs) and multicomponent hybridnanoparticles; 2) fabrication and characterization of ordered nanoparticle arrays with tailored propertiesand interactions, created by the integration of self-assembly and microfabrication techniques; 3)development of functional materials and devices having potential for spintronic and high frequency applications. Non-Technical Broader Impact: The proposed work contains a strong educational component with a goal ofcultivating researchers with multidisciplinary skills and integrating the PI's research expertise into educational activities. These research activities lie at the intersection of physics, chemistry and engineering, involving material synthesis, device fabrication, and structural and physical property characterizations. This combination offers interdisciplinary and multi-skill training to students and postdocs. Through collaboration with IBM researchers, selected graduate and undergraduate students will be offered industrial internships. This exposure will broaden their horizons and prepare them forcareers in either academic or industrial settings. The PI expects to increase participation of women and minority students in his research program via targeted recruiting, in the form of providing research experience for undergraduates, assistantships and internships. Undergraduate students will be recruited to develop a magnetotransport measurement system, which will be used for the Department's Advanced Lab course as well as a unique tool for spin polarized transport studies. Systematic approaches will be employed to stimulate abstract thinking and logical reasoning in the teaching of undergraduate introductory physics. Research results and current and future technology trends will bepresented to a broader audience including K-12 science teachers and students, targeting high needs of inner city and Native American schools in the Buffalo area, through developing hands-on material science tools and resources.
This CAREER proposal aims to understand and manipulate spins and magnetism in self-assembled nanoparticle arrays with potential for spintronic and high frequency applications. The major outcomes of this funded research are summarized below: 1. We have successfully synthesized novel multi-component nanoparticles, and demonstrated that they exhibit simultaneous magnetic, semiconducting and plasmonic properties. Properties originating from their synergistic interactions have also been demonstrated. These multi-component nanoparticles may serve as fundamental building blocks for multi-functional devices. The work has been cited hundreds of times and featured in many review articles and journal reports. 2. We have integrated self-assembly with lithographic patterning to fabricate magnetic nanoparticle based charge transport devices. These devices show that magnetic field can be used to tune the charge transport due to the unique spin properties of the electrons in the specific magnetic materials. This work may provide the knowledge needed for using nanoparticles in future flexible electronic, spintronic and photovoltaic devices. 3. We have used ac-magnetic field and magnetic nanoparticle to generate local heating on cell membrane. This local heating opens up the calcium channel, and leads to remote control of neuronal function. This work paves the way for in vivo applications of magnetic nanoparticles for neuron stimulation. 4. We also synthesized transition metal doped semiconductor quantum dots, and used photoluminescence in a magnetic field to study the interactions between these dopants and charge carriers. Understanding such interactions in confined geometry is important for applications of such systems in spintronics. We are the first to study such properties in lead salts such as PbS nanoparticles. This funded research has led to about 20 publications. They have been cited extensively. 3 Ph.D. and 1 master’s students graduated with the support from this grant. About 12 undergraduate students participated in the summer research in the PI’s lab, mostly from underrepresented groups. Other educational activities include high school visits, department open house and public lectures. The PI also developed a few modules used for outreach activities, using quantum dots and magnetic nanoparticles synthesized in house.
