. . ""• * - - .

T . . - ..

.- - ,.

'

-., •7-1. 'Vi t-

• ••

A H». f-

)

.-. . ,\\ .

i'

«. ; - '

f

Fig.10.8. Beispiel AgBr. Lender warden bei hoheren T auch anharmom'sche

Effekte slchtbar, s.d. (10.20) nicht zuverlassig 1st.

35

30

20

Fig. 10.8.

15

101300

Cp = 12 +0.035 F '

400 500 600T e m p e r o t u r , K

700

me von Silberbromid bcl k o n s t a n l e m Druck. Es zel£l s ich ein zusSlz-licher Dcllraf: zur eperilischen Wkrme , der von der Bi ldung von G i t l e r f e h l -steJlen herruhrt . [Sach R . W . Chris ty und A. W. Larson, J. Chem. P h y s . 1 9 .517 (1951).]

.

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cn (^

ci ^QJ

01 j_ t.'»- 3 «3U_ 4-> JD

pump

Fig. 2.16. Field ion microscope with moveablc tip and massspectrometer attachment [2.15].

Fig. 2.18. Field ion micrograph of a tungsten tip [2.15].

0;oft

FTV)-l

o-

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p>-5

ij

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i

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if

0

8

.

l«i -

OI I

rnIInr>

I!

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I)

NaSource

-\AA> y s^1.27 MeV

Scintillator

Fig. 1. Scheme of the positron lifetime experiment in fast-fast coincidence. The lifetime ismeasured as the time difference between the appearance of the start and stop "/-quanta(PM—photomultiplier, SCA—single-channel analyzer). The amplitude of the time-to-amplitude converter (TAC) analog output pulse is proportional to this time difference. The\vhole lifetime spectrum N(t) is stored in a multi-channel analyzer (MCA).

10eF

10-

cn

I 10*oO

1QJ r

As-grown CzSi

Plastically deformed Si

0 1 2 3 4 5

Time [ns|

Fig. 2. Experimental positron lifetime spectra obtained in as-grown and in plasticallydeformed Czochralski-grown (Cz) silicon (Htibner et al. 1997b). The curve of the deformedsample (3 % strain, deformation temperature 775 °C). is located significantly higher,indicating the occurrence of long-lived lifetime components. After the decomposition of theupper spectrum, the obtained lifetime components T^ and 13 are added as straight lines inthe semi-logarithmic plot for illustration. The TI component is not indicated as a straightline {TI = 120 ps). Only one lifetime component corresponding to the positron bulk lifetimeTb is found in the as-grown sample. The deviations from the straight line at higher times aredue to annihilations in the source and the background contribution. The Gaussian-like shapeof the left part of the curve is mainly caused by the resolution function.

* .

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10-Tm 600 "C 500

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400 300

[0

CH8 I0

'

i nI.I 1..1 1.5 1.7 1.9

Fig. 10.2. Experimental results of various authors fo r theT-dependence of cv = 3(A///~Aa/a) in a luminium. The experimentalerrors give rise to an unccr t r 'n ty Acv = ± lO""* shown as Tour errorbars. Measurements of the positron l i f e t ime at vacancies give theslope of the f u l l line in the range shown accurate to ±10"7. Themaximum sensitivity of this method is at Cy^S x IO"6 (arrow). Theopen triangles are derived from measurements of the specific heat.After A. Seeger [10.1].

.'•' ^ r ' " ' — ' » ' ' - ' , .- ' _ , . , • . . . • - < •

: .

'V

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120 h 160

Fig. 10.4. The frac t ion Apc;/Ap0 of the change in res idua l resis tanceremaining in gold wires quenched from 700 °C a f t e r t emper ing for /hours at 40 °C or 60 °C.'

" • *: «. - 1 ' ;- •••'

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Szennyezo ionnal keltett vakancia

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~Na+

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Nem fuggetlen ponthibak

lonos kristalyoknal a lokalis tdltessemlegessegmegkdvetelese is szukseges.

Ezt Lagrange-multiplikatorokkal vehetjuk figyelembe aszabadenergiaban.

Legegyszerubb eset:

q es -q toltesu ionokbol allo racs. Vakanciak keltesienergiaja e- es £+, szamuk n- es n+.

s_ —

n+=Ne

Toltessemlegesseg feltetele: n = n

A Tn - Ne

Szincentrumok

F-centrum

/UUD.IU.iU.

Bonding in Materials

Point Defects in Ionic Solids

1. oldal, osszesen: 1

Vacancies are required in ionic solids, just like they are for other types, BUTThe vacancies must be formed:in such a way that the solid remains charge neutral.Single vacancies cannot be formed because they leave behind a charge center.Two main ways to create point defects in ionic solids without causing charge imbalance:

o Correlated vacancies: Schottky defectso Correlated vacancy-interstitial groups: Frenkel defects

Schottky Defects: [100) NaCI

Exercise: What is the most likely Schottky defect structure in Zr02?

00

httD://www.mse.uiuc.edu/info/msel82/tl42.html 2006.10.10.

Bonding in Materials

Point Defects in Ionic Solids

Frenkel Defects: [100] MgO

1. oldal, osszesen: 1

Exercise: What is the most likely Frenkel defect in ZrO2?

http://w\v\v.mse.uiuc.edu/info/msel82/tl43.html 2006.10.10.