| Space technology and nuclear reactor under irradiation environment have to meet the standards of enhanced safety and economical compatibility. This research contributes to this objective through the understanding of irradiation induced nano-structural, electrical and magnetic property changes in nanomaterials. Fe3O4and Fe-Fe3O4nanoparticle (NP) granular films, created by our third generation nanocluster deposition system, were irradiated. The pristine magnetite (Fe3O4) granular films with an average grain size of 3 nm are superparamagnetic in nature. These films enriched ferromagnetic behavior under the irradiation exposure of 5.5 MeV Si2+ions to a fluence of 1016ions/cm2at room temperature. After irradiation, the average grain size and magnetic domain size of the films showed dramatic increase. On the contrary, Fe-Fe3O4core-shell NP films under 5.5 MeV Si2+ion irradiation showed that the core size unchanged but the shell size increased and shell phase was transferred from Fe3O4to FeO with a small reduced magnetic moment. This is a fascinating behavior because this meets the requirement for advanced data storage applications in extreme irradiation environment in space. Very interesting point is that the nano-structural evolution under irradiation features size growth, phase transition, particle aggregation, and formation of nanowire-like network as shown in our recent samples of NP films, which makes a super-exponential decay of the electrical resistance of the films with irradiation dose, suggesting that this type of nanomaterials may possess an intrinsic merit for development of an ultra-high sensitive advanced online monitor for radiation detection.
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Dr. You Qiang is an adjunct professor in Environmental Science and a tenuredprofessor of Physics at the University of Idaho, Idaho, USA. He is chairman (2012-2013) and member of Idaho Academy of Science. He received his MS degree at Harbin Institute of Technology (HIT) and Chinese Academy of Space Technology (CAST) in 1985, and Ph.D. degree in 1997 at University of Freiburg, Germany. He was a research faculty at the University of Nebraska-Lincoln, USA, from 1999 to 2002. His research is focusing on physics of nanomagnetism and magnetic nanoparticles for more than 30 years. He applies the nanomaterials in nuclear energy, environmental science, including synthesis of monodispersive nanoclusters and nanocluster-assembled composites; characterization of magnetic and optical properties as well as transport properties by conductivity, optic and susceptibility, and theoretical investigation of magnetic nanoparticle interactions. He has published more than 100 refereed papers (AFM, JACS, PRB, APL, En&S…) and 4 book chapters, given more than 110 invited talks at international conferences, universities and institutions, and served as editor for several international scientific journals, member for international conferences and society committees, including MRS, CleanTech, NanoTech and IMC meetings. He organized and chaired more than 20 conferences and sessions such as INTERMAG, MMM, APS and NW-APS meetings.
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