SCIENCE AND TECHNOLOGY OF SELF-ASSEMBLED MAGNETIC AND SUPERCONDUCTING NANO ARRAYS

D. Kumar, North Carolina A & T State University, DMR-0403480

(a) Cross-section high-resolution STEM-image of YBCO film embedded with Y2O3 nanoparticles (indicated by arrows) are clearly discernible, with average size and separation of ~5 nm and ~10 nm, respectively (b) High resolution STEM image of one Y2O3 nanoparticle showing its coherent growth in the YBCO matrix.

(a) 3-D self-assembled Ni-nanoparticles in Al2O3 thin film matrix. (b) STEM-image of a single Ni-nanoparticle obtained using the STEM at ORNL with highest resolution in the world.

By maneuvering the misfit strain between nanoparticles and the surrounding thin film matrix, self-assembled ordered structures of nanomagnetic particles in nonmagnetic thin film matrices and nanodimensional impurity defects -acting as pinning centers- in a high temperature superconducting YBa2Cu3O7-x thin film matrix have been achieved using a pulsed laser deposition technique, shown schematically in adjacent figure. The abilities to create an ordered array of magnetic nanoparticles in thin film matrix and to embed coherent array of non-reactive nanoparticles in superconducting thin film matrix are expected to result in the fabrication of new devices in the area of magnetic recording, biomedicine, and the development of second-generation “coated conductor” films for power applications.

(b)

SCIENCE AND TECHNOLOGY OF SELF-ASSEMBLED MAGNETIC AND SUPERCONDUCTING NANO ARRAYS

D. Kumar, North Carolina A & T State University, DMR-0403480Broader Impact: New Course Development: The course (MEEN 660: New Methods in Thin Film Synthesis) was taken by eight MS and four senior undergraduate students. The course is planned to be inducted in permanent –course-curricula of Mech. Eng. Dept. at NCAT. Infrastructure development: A physical property measurement system has been purchased which is used by several faculty and students members at NCAT enhancing their research and educational standard significantly.Salient Publications (total exceeds 15)J. Mater. Res. (Invited, 2005), Meta. Mate.Trans. 36A, 277-294 (2005), J. Appl. Phys. 97 (2005), J. Nanosci. Nanotechno. 4, 726 (2004), Supercond. Sci. Tech. (submitted)Invited presentation (more than 10)Kumar (2: MRS & TMS), Hebard (2: APS & MRS)), Pennycook (1: MRS), Narayan (4: MRS, TMS Campbell Lecture), Gapud (1:MRS) International dissemination of resultsNIRT-PI was the lead organizer of a symposium on “Magnetic nanoparticles and nanowires” during MRS 2005 Spring Meeting in San Francisco that had ~ 15 invited oral presentations, 50 contributed oral presentations, and 30 poster presentations from within and outside USA.

Community service and Contributions to Human Resources:Outreach: A half-day science exhibition was organized at NCAT for 5th grade students (~140) and teachers (~10) from Monticello Brown Summit Elementary School in Guilford County, NC. The exhibition included tours to various laboratories, demonstrations of simple experiments (highly magnified images via scanning electron microscope, levitation of high temperature superconducting pallets in liquid nitrogen), and a lecture about nano dimension and fascinating applications arising from nanomaterials.

Student graduated: S. Dana, MS; J. Bradley, MS; T. Davis, BS (NCAT); H. Zhou, Ph.D. (NCSU).Current students: A. Gupta, A. Paige, S. Viswanathan, MS ( NCAT); G. Trichy, Ph.D. (NCSU); R. Rairigh, Ph.D. (UF); J. Steed, J. Jordon, B. Killian, B. Spencer, J. Green, Undergraduates (NCAT) Post doc fully/partially supported: J. Abiade (NCAT), A. Tiwari (NCSU), A. Gapud (ORNL)