Study of Electrical Percolation in CrO₂/Cr₂O₃ nanoparticle composite system

Percolation is a random probabilistic process that triggers a phase transition in disordered systems. In this work we investigate the classical percolation behavior in a CrO₂/Cr₂O₃ half-metal/insulator composite system. Cr₂O₃ was obtained by annealing of CrO₂ powder in air; 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 by studying the changes in the electrical resistance of the pellets with different volume fractions. Experimental results are compared with theoretical calculations, which were carried out via the combination of mechanical contraction method and Monte Carlo simulations for this binary composite system of non-overlapping hard spherocylinders.