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24.4 Dielectrics. 24.6 Gauss’s law in dielectrics. 24.5 Molecular model of induced charge. Introduction to Dielectrics. 24.4 Dielectrics. d. Separate two metal sheet with small gap d. Increases the maximum possible potential difference between the capacitor plates.
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24.4 Dielectrics 24.6 Gauss’s law in dielectrics 24.5 Molecular model of induced charge Introduction to Dielectrics
24.4 Dielectrics d Separate two metal sheet with small gap d Increases the maximum possible potential difference between the capacitor plates Increase the capacitance
24.4 Dielectrics Definition of dielectric constant K Capacitance with dielectrics Capacitance without dielectrics Recall: To store same amount of charge Q, voltage required is reduced for higher K materials Note, K will change respect to temperature and frequency. Also, in a single crystal, K is different along different crystal axes. Strontium titanante (SrTiO3) with K=310 Chromia (Cr2O3) with K=13
24.4 Dielectrics Strontium titanante (SrTiO3) with K=310 Two-dimensional electron gas with universal subbands at the surface of SrTiO3 A. F. Santander-Syro, et al. Nature, 469, 189 (2011) Metallic and Insulating Oxide Interfaces Controlled by Electronic Correlations H. W. Jang, et al. Science, 331, 888 (2011)
24.4 Dielectrics Chromia (Cr2O3) with K=13 Robust isothermal electric control of exchange bias at room temperature Xi He, et al. Nature Materials, 9, 579 (2010) Imaging and Control of Surface Magnetization Domains in a Magnetoelectric Antiferromagnet Ning Wu, et al. Phys. Rev. Lett. , 106, 087272 (2011)
24.4 Dielectrics Recall: and E0 E Also recall: and Definition of the permittivity and
24.4 Dielectrics +Q Example: E1 d/2 K1 E0 V E2 K2 d/2 -Q = =
24.4 Dielectrics High Voltage Ground Cr2O3 Ground Dielectric breakdown or Dielectric strength Air
24.6 Gauss’s Law in Dielectrics Recall: Dielectrics Conductor A A A
24.6 Gauss’s Law in Dielectrics Example: K E1 ra r rb E2