Physics ABC Seminar: "Experimental and theoretical insights of percolation transition in nanoparticle composites", Shiva Pokhrel and Brendon Waters, Wayne State University

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Date: February 25, 2020
Time: 3:30 p.m. - 4:30 p.m.
Location: Physics & Astronomy Department - Liberal Arts and Sciences #245 | Map
666 W. Hancock
Detroit, MI 48201
Category: Seminar

Experimental and theoretical insights of percolation transition in nanoparticle composites

Shiva Pokhrel and Brendon Waters
Department of Physics and Astronomy, Wayne State University

Percolation, one of the standard models for disordered system, is a random probabilistic process which shows a phase transition. In this work, we investigate a flexible model system based on half-metallic spherocylindrical CrO2 nanoparticles, which can be gradually converted by annealing from metallic (CrO2) to insulating (Cr2O3) state. The composite samples with varying volume fraction were prepared by mixing Cr2O3 with CrO2. The percolation threshold and the power law scaling exponent near the threshold were identified experimentally by studying the changes in the electrical resistance of the pellets with different volume fractions. To more thoroughly investigate the microscopic origins of the observed trends in the bulk properties of the nanocomposite, a series of hard-particle simulations were conducted using the combination of Monte Carlo and mechanical contraction methods that can produce dense random packing of non-overlapped spherocylindrical particles. Using a scaling method to extrapolate to the infinite system-size limit, we determined several properties of critical behavior of the system and found them to be in good agreement with experimental results.


Zhi-Feng Huang




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