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Lecture 10.1. Dielectric properties

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1 Properties of Advanced Materials (Dielectric Properties-Part I) Dr. Farhat Nosheen Lecture CHEM3115 Inorganic Material Chemistry 2 Key Concepts Dielectric Properties of advanced materials • • • • • • Introduction Dielectrics Polarization Capacitance Capacitance and permittivity Polarizability and polarization 3 Introduction • A dielectric (or dielectric material) is an electrical insulator that can be polarized by an applied electric field. • When a dielectric material is placed in an electric field, electric charges do not flow through the material as they do in an electrical conductor but only slightly shift from their average equilibrium positions causing dielectric polarization. Examples of dielctric materials: • porcelain (ceramic), • glass, • plastics, • oxides of various metals. • Some liquids and gases can serve as good dielectric materials. • Capacitor, device for storing electrical energy, consisting of two conductors in close proximity and insulated from each other. 4 Dielectrics properties 5 Polarization 6 Capacitance 7 Capacitance and permittivity 8 Polarizability and Polarization The electric susceptibility χe of a dielectric materials is a measure of how easily it polarizes in response to an electric field. This, in turn, determines the electric permittivity of the material and thus influences many other phenomena in that medium, from the capacitance of capacitors to the speed of light. 9 10 Reference • An introduction nanotechnology, 2015. to nanoparticles and Maria Benelmekki 11 Assignment • Find the examples of dielectric nanomaterials 12 Thanks 13