Chapter 7

Electrical properties

Typical values of electrical conductivity

Formation of polyacetylene and polyethylene

Polyparaphenylene and polypyrrole

TCNQ, TTF,…

Electrical resistance of YBa 2 Cu 3 O 7

Meissner effect showing repulsion of a superconductor

Levitation inaction

Type I and II superconductors

Some superconducting materials

Perovskite-related cuperate structures showing octahedral

ABO 3 YBa 2 Cu 3 O 6 A 3 B 3 O 9-3

Y Ba

Rb x WO 3 BaTiO 3 YBa 2 Cu 3 O 7 A 3 B 3 O 9-2

Cu + Cu 2+ Cu 3+ Cu 2+

Perovskite-related cuperate structures showing square planar

Cu +3 , d 8 ; Cu +2 , d 9 ; and Cu(I), d 10 s 1

Crystal structures of YBa 2 Cu 3 O 7 and YBa 2 Cu 3 O 6

T c vs oxygen content YBa 2 Cu 3 O

d Oxygen loss on heating

YBa 2 Cu 3 O

7 Pressure of O 2 in bars

T c as a function of lattice parameter for K 3 C 60 The interaction of C 60 3 anions determines conductivity.

more metallic less metallic

Conductivity of metals, semiconductors and insulators

Relation between electronic properties and magnitude of the band gap

p-type semiconductivity in gallium-doped silicon

n-type semiconductivity in arsenic-doped silicon

A pn junction

Migration of cation vacancies

Schematic ionic conductivity of doped NaCl crystal

s

= ne

m

0 exp(-E m /RT) n = N exp(-E f /2RT)

High temp

Na 1-2x Mn x V x Cl

Low temp E m E f = activation energy of cation migration = activation energy to form Schottky defects

Pathway for Na + migration in NaCl

Triangular interstice

Ionic conductivity of pure NaCl as a function of temperature

Conductivity in NaCl crystals

Migration of interstitial Ag + ions by direct interstitial jump and indirect interstitialcy mechanism

Effect of Cd +2 on conductivity of AgCl crystals

s

depends on [Ag i + ]

This indicates more than one mechanisms for conductivity.

Addition of Cd 2+ decreases [Ag i + ] first, then increase [V Ag ] .

Solid electrolytes as intermediate between normal crystalline solids and liquids

Ionic conductivity of some solid electrolytes

HT LT

Oxide layers in



-alumina

Oxide packing in



- and



’’-alumina

Conduction plane in



-alumina

An example of F anionic conductor Conductivity of PbF 2

Some oxide ion conductors

Electrochemical cell containing a solid electrolyte

Components of a secondary lithium battery

A thin film electrochromic device

Oxygen concentration cell

Dielectric material between two plates of a parallel plate capacitor

Hysteresis loop of a ferroelectric

Some ferroelectric materials

Spontaneous polarization of a TiO 6 BaTiO 3 octahedron in

Dipole orientation in a ferroelectric, an antiferroelectric, and a ferrielectric

Ferroelectric domains separated by a domain wall or boundary

Dielectric constant for barium titanate ceramic

e

‘= C/(T-

q

)

Curie-Weiss Law

antiferroelectric paraelectric

Antiferroelectric-ferroelectric transition in PbZrO 3 as a function of applied field

ferroelectric antiferroelectric

Displacement of phosphorus within a PO 2 (OH) 2