Related Experiment Video
Updated: Nov 8, 2025

Phase Diagram Characterization Using Magnetic Beads as Liquid Carriers
Published on: September 4, 2015
Percolation Behaviour in the Magnetic Permeability and Electrical Conductivity in Conducting Magnetic - Insulating
David S McLachlan1, T B Doyle2,3, Godfrey Sauti4
1School of Physics, University of the Witwatersrand, Johannesburg, 2050, South Africa.
Abstract:
Experimental results of the complex magnetic permeability (μ) and the electrical conductivity (σ) of a granular paramagnetic Gadolinium Gallium Garnet (GGG: 0.3 to 26 Vol. %) and Teflon (PTFE) system are presented, and discussed in relation to previously published (conductivity) and unpublished (permeability) studies on granular Fe3O4 - talc and Ni - talc wax systems. In these systems, plots of the real conductivity ( ) against the volume fraction (φ) lie on a characteristic sigmoid curves that when fitted to the Two Exponent Phenomenological Percolation Equation (TEPPE), confirm the existence of "percolation microstructures" with critical volume fractions (φ c). The plots of the real and imaginary permeability ( ) and ( ), satisfactorily fit to the TEPPE using the φ obtained in each case from the "conductivity" measurements. In all three cases, the conductivity results gave the exponent t > 2, and the permeability results gave t < 1.
More Related Videos
Related Concept Videos
Magnetic Susceptibility and Permeability
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
Magnetostatic Boundary Conditions
Ferromagnetism
Paramagnetism
Theory of Metallic Conduction
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
Electrical Conductivity
In a practical conductor, an applied electric field may be sustained, causing a flow of electrons, which produce a current. The differential form of the current, the current density, is related to the electric field.
More generally, it is related to the force per unit charge, which involves the...

