![]() |
Here are some quick questions: | ||||||||||||
![]() |
The answers are sometimes (and possibly only indirectly) contained in the links. | ||||||||||||
![]() |
2.1.2 Frenkel Defects | ||||||||||||
![]() |
Why do we need "Frenkel" and "Schottky" defects besides vacancies, self-interstitials and their agglomerates? | ||||||||||||
![]() |
Draw a schematic picture of a crystal with "Frenkel" and "Schottky" defects. What kind of "conservation laws" do you have to consider, and why does that lead to a fundamental difference between the two defect kinds? | ||||||||||||
![]() |
What kind of charge would "the" vacancy carry in a NaCl crystal? (Consider only the realistic case). | ||||||||||||
![]() |
Give some crystals where Frenkel disorder prevails. | ||||||||||||
![]() |
Give an (approximate) equation for the concentration of Frenkel defects an discuss the important terms | ||||||||||||
![]() |
2.1.3 Schottky Defects and 2.1.4. Mixed Defects | ||||||||||||
![]() |
What, quite generally, is the Debye length? | ||||||||||||
![]() |
How does the Debye length come into consideration when discussion Schottky defects (and Frenkel defects)? | ||||||||||||
![]() |
If the formation enthalpies of two defect kinds differs by roughly ...???...eV, one defect type will be dominating and the other one can be neglected. | ||||||||||||
![]() |
Why do we usually consider either Schottky or Frenkel defects in ionic crystals but not mixed defects? For the answer check this exercise. | ||||||||||||
![]() |
Can you predict for a given ionic crystal which kind of defect type (Schottky or Frenkel) will be prevalent? | ||||||||||||
![]() |
Discuss the details in the following set of equations: | ||||||||||||
| |||||||||||||
![]() |
Derive in an equivalent way the final relation for Schottky defects: | ||||||||||||
|
2.2.2 Local and Global Equilibrium
Exercise 2.1-6: Enthalpy difference for the limiting cases of Schottky or Frenkel Defects
Point Defects in Ionic Crystals
© H. Föll (Defects - Script)