X-RAY DIFFRACTION STUDY ON LIQUID AND
NON CRYSTALLINE SOLID GALLIUM, BISMUTH
AND MERCURY
A. Bererhi, A. Bizid, L. Bosio, R. Cortes, A. Defrain, C. Segaud
To cite this version:
A. Bererhi, A. Bizid, L. Bosio, R. Cortes, A. Defrain, et al..
X-RAY DIFFRACTION STUDY ON LIQUID AND NON CRYSTALLINE SOLID GALLIUM, BISMUTH
AND MERCURY. Journal de Physique Colloques, 1980, 41 (C8), pp.C8-218-C8-221.
<10.1051/jphyscol:1980856>. <jpa-00220363>
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JOURNAL DE PHYSIQUE
ColZoque C8, supplBmeni: au n08, Tome 41, aoCt 1980, page Cg-218
X-RAY DIFFRACTION STUDY ON L I Q U I D AND NON CRYSTALLINE SOLID GALL1 UP?, B l SYUTH AND PIERCURY
A. Bererhi, A. ~ i z i d * , L. Bosio, R. Cortes, A. Defrain and C. Segaud
Groupe de Recherche n04 du CNRS "Physique des Liquides e t Electrochimie", assoeie' ri
l'llniversitd Pierre e t Marie Curie, 4 place Jussieu, 75230 Paris Cbdes 05, France.
*Universite' de
Tunis, Facult6 des Sciences, Ddpartement de Physique, Campus Universitaire
1006 Le Belvdde're, Tunis, Tunisie.
Abstract.- An attempt is made to compare the structures deduced from X-ray measurements on some
pure metals, both in the liquid and the non crystalline state. With Ga and Bi, the liquid and the
amorphous solid structures show some similarities and seem to be correlated with the solid phase
which occurs when crystallisation takes place. Different behaviour is found with Hg : the liquid
structure factor differs from the structure factor in the amorphous state whose main peak is
symmetric in form.
INTRODUCTION
The p r o p e r t i e s of most o f t h e l i q u i d metals
r i d e monochromator i n t h e d i f f r a c t e d beam. The
r a d i a t i o n s were CuKa and NoKa. By d i v i d i n g t h e sam-
have been s u c c e s s f u l l y described by a hard sphere
p l e i n t o small d r o p l e t s , i t was p o s s i b l e t o study
d e s c r i p t i o n i n c o n j o n c t i o n w i t h p e r t u r b a t i o n tech-
t h e s t r u c t u r e o f supercooled l i q u i d s : f o r Cia and
Hg t h e d i s p e r s i o n s were prepared by using an u l t r a -
niques [I].
Concerning t h e non c r y s t a l l i n e s o l i d
s t a t e , t h e dense random packing o f hard spheres[2]
sonic generator t o disperse t h e molten metals w i t h i n
i s apparently a s a t i s f a c t o r y approach t o model 1ing
e t h y l alcohol s a t u r a t e d w i t h sodium o l e a t e , thus
atomic arrangements i n metal 1i c glasses. However,
a1 l o w i ng experiments under t h e normal me1ti ng p o i n t
these d e s c r i p t i o n s completely f a i l when c r y s t a l l i -
a t supercooling o f 140 and 61 K r e s p e c t i v e l y ; f o r
s a t i o n does n o t form c l o s e packed s o l i d s ; i n these
B i , t h e procedure o f forming d r o p l e t s t o achieve
cases, t h e l i q u i d s t r u c t u r e f a c t o r o f t e n has a
l a r g e supercooling [41 was n o t convenient f o r X-ray
shoulder o r a hump on t h e high-angle s i d e o f t h e
i n v e s t i g a t i o n because o f extraneous Braggs peaks
p r i n c i p a l peak and, i n amorphous s t a t e , n e i t h e r t h e
provided by the oxyde-coated drop1 e t s : t h e d i sper-
s t r u c t u r e f a c t o r nor t h e p a i r c o r r e l a t i o n f u n c t i o n
sions were prepared by shaking
show t h e c h a r a c t e r i s t i c s p l i t t i n g o f t h e second
hexadecanol w i t h some s t e r o l s as s u r f a c t a n t s , t h e
max imum
.
t h e molten B i i n
maximum supercooling was thus l i m i t e d t o 68 K.
The present paper describes t h e t y p i c a l behav i o u r of t h r e e o f these metals (namely Ga, B i and
I n a l l cases, samples were cooled o r heated
in VaCUUum chamber i n which t h e pressure could be
Hg) which o f f e r t h e experimenters t h e unique opport u n i t y o f i n v e s t i g a t i n g by X-ray d i f f r a c t i o n mea-
reduced
surements t h e s t r u c t u r e ( i ) o f t h e normal and su-
torr except f o r Hg where t h e cham-
b e r was f i l l e d w i t h helium [51.
Nominally pure amorphous metals a r e o n l y avai
-
percooled l i q u i d , ( i f ) of t h e amorphous s o l i d Pre-
l a b l e by vapour d e p o s i t i o n onto l i q u i d helium c o o l d
pared by vapour d e p o s i t i o n onto substrates cooled
s u b s t r a t e s [21 : the low temperature condensation
a t very low temperature.
apparatus, c o n s i s t i n g ofan i o n i c u l t r a - h i g h vacuum
system w i t h an e l e c t r o n gun and a l i q u i d helium
EXPERIMENTS
An X r a y s diffractometer
c r y o s t a t , i n c o n j u n c t i o n w i t h t h e X-ray d i f f r a c t o m e o p e r a t i n g i n a symne-
t r i c a l r e f l e c t i o n mode has been used t o determine
t e r b u i l t on t h e pumping system, has been described
t h e s t r u c t u r e o f b o t h l i q u i d and amorphous s o l i d
elsewhere [61 ; t h e o n l y m o d i f i c a t i o n s consisted i n
t h e use o f a post-specimen monochromator and a spe-
metals.
c i a 1 device f o r mercury d e p o s i t i o n .
The experimental arrangement f o r t h e measure-
Though t h e y were t h i n ( r e s p e c t i v e l y 3, 0.2 and
ment o f t h e s c a t t e r e d i n t e n s i t i e s by l i q u i d s consis-
0.1 pm For Ga, B i and Hg) t h e amorphous f i l m s were
t e d o f a t h e t a - t h e t a d i f f r a c t o m e t e r [31 w i t h a sta-
t h i c k enough f o r X-ray d i f f r a c t i o n study. Three
t i o n a r y , h o r i z o n t a l sample and a bent l i t h i u m f l u o -
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1980856
1
I""
--
&-'I
2
4
ilqur.
5
Pal- c l v . l r r l a
6
funcllon for , l o u l d and
8
10
aorawr IIINUI
-
c8-220
JOURNAL DE P H Y S l Q U t
wavelengths were used, CrKa,
CuKa and MoKa, t o ob-
f r e e z i n g occurs i n supercooled l i q u i d Ga i t i s r a -
t a i n r e l i a b l e d a t a i n t h e low and h i g h wavevector
t h e r t o t h e metastable @-phase whereas t h e normal
q = 4nsine/X and a l s o t o t a k e advantage of t h e
s t a b l e form has always been observed t o occur when
wavelength dependence o f X-ray absorption.
c r y s t a l l i s a t i o n takes p l a c e i n supercooled l i q u i d
Hg and B i ; moreover, some authors used t h e c r y s -
RESULTS AND DISCUSSION
t a l l i n e l a t t i c e as a framework f o r d e s c r i b i n g li-
The s t r u c t u r e f a c t o r S(q) o f l i q u i d Ga, B i and
Hg are shown i n F i g . 1, 2 and 3. Both Ga and B i
q u i d Ga 181, B i 191 and Hg [5, 101 by a quasi
c r y s t a l l i n e s t r u c t u r e model : t h e y a l l e s t a b l i s h a
e x h i b i t a shoulder on t h e r i g h - a n g l e s i d e whereas
close correspondence between the l i q u i d and corres-
Hg o n l y shows a hump ; i n Ga, t h e shoulder gradual-
ponding c r y s t a l l i n e s o l i d s t r u c t u r e .
The sane conclusions may be transposed t o t h e
l y increases when t h e temperature i s lowered b u t i n
Hg and B i these anomalies remain unchanged though
n o n - c r y s t a l l i n e s o l i d Ga and B i : i n amorphous
they a r e l e s s e v i d e n t a t h i g h temperature because
s t a t e these two metals show e v i d e n t resemblances t o
o f the broadening o f t h e f i r s t maximum. The most
t h e corresponding l i q u i d b o t h i n s t r u c t u r e f a c t o r s
n o t i c e a b l e e f f e c t o f t h e temperature on t h e s t r u c r e d u c t i o n o f t h e f i r s t peak h e i g h t S(qo) as tempe-
( F i g . 1 and 2) and i n p a i r c o r r e l a t i o n f u n c t i o n s
( F i g . 5 and 6) ; because o f t h e absence o f d i f f u s i v e displacements i n t h e s o l i d s t a t e , t h e observed
r a t u r e r i s e s ; t h e temperature dependence of S(qo)
o s c i l l a t i o n s a r e more pronounced and t h e shoulders
i s i d e n t i c a l f o r these t h r e e metals, as shown i n
seen i n 1i q u i d s appear b e t t e r defined.
t u r e f a c t o r s i s t h e damping i n h i g h q range and t h e
F i g . 4 where t h e r a t i o o f t h e h e i g h t [ S ( q o ) l T t o
that Observed
at the
point [S(qo)l~m are
p l o t t e d as a f u n c t i o n o f t h e reduced temperature
IJe t h i n k t h a t such a s i m i l a r i t y between t h e
l i q u i d and t h e amorphous s t r u c t u r e s -supported by
t h e f a c t t h a t t h e amorphous f i l m s do c r y s t a l i i z e t o
t h e same v a r i e t i e s t h a t supercooled l i q u i d s - must
be connected w i t h t h e process used t o o b t a i n amorphous samples. Indeed, i n p r e p a r i n g Ga and B i f i l m s
by vapour deposition, atoms ( o r i o n s ) impinge o n t h e
[O B i
cooled s u b s t r a t e w i t h an i n i t i a l k i n e t i c energy
wnnous
s u f f i c i e n t t o d i s t u r b t h e atoms p r e v i o u s l y deposit e d and t o r a i s e temperature l o c a l l y up t o t h e mel-
8 H~
t i n g p o i n t ; o b v i o u s l y t h i s e f f e c t concerns few
atoms around t h e p o i n t s o f impact and t h e quench
r a t e i s r a p i d enough t o garantee n o n - c r y s t a l l i n e
1L
T I T~
I
0.5
rlqur.
4
atl lo o f me U r p n r siq,:
factor 1:mat Wsennt
I
1.5
I
1.0
-
s o l i d f o r m a t i o n w i t h some reminiscence o f l i q u i d
s t a t e . Because o f t h e h i g h vapour pressure o f merc u r y i t i s p o s s i b l e t o produce f i l m s w h i l e the eva-
of :M *frtt oeak of cne I ~ g u l dsmmctum
r l t l m mtnt in. rlw:d rr a
c?os. um
' u n c t m a t tn, reducnt t-raure
- / ~ n In. f u l l ltn -n>ch reorerents tne c u n e qlv.n
¶y llqnr [ I l l for l a am.? s u i r N s C N n
w o l ~ * t *In~ta. rurrcmlca %ram
p o r a t i o n c r u c i b l e i s maintained a t low temperature;
From S(q) , t h e p a i r c o r r e l a t i o n f u n c t i o n s ,
g ( r ) ( F i g . 5, 6 and 7), can be obtained i n t h e
standard way by F o u r i e r t r a n s f o r m a t i o n : t h e s t r u c t u r e o f l i q u i d Ga and Hg remains q u i t e unchanged
when t h e temperature i s lowered except some i n c r e a se i n t h e l a r g e range c o r r e l a t i o n . I t i s o f p a r t i -
atoms reach t h e s u b s t r a t e w i t h o u t ~ r o d u c i n at o o
<
much damage : t h e s t r u c t u r e f a c t o r o f t h e amorphous
f i l m thus obtained ( F i g . 3) e x h i b i t no shoulder on
t h e f i r s t peak and r a t h e r looks l i k e t h e hard spher e d e s c r i p t i o n and t h e n o n - c r y s t a l l i n e s o l i d s t r u c t u r e o f mercury ( F i g . 3 and 7) n o t a b l y d i f f e r s f r a n
t h a t i n the l i q u i d state.
c u l a r i n t e r e s t t o n o t e t h a t e x ~ e r i m e n t s on Ga and
The normalized f i r s t peak h e i g h t o f t h e s t r u c -
Hg have been performed i n t h e s t r o n g l y supercooled
state close ti, the ul
stability
limit
of the
l i q u i d s t a t e b u t no s t r i k i n s feature is
seen either
"
t u r e f a c t o r obtained from t h e experiments c a r r i e d
Out
On
the three
are
in
i n S(q) o r i n g ( r ) concerning any i n c i p i e n t ordered
F i g . 4 : t h e r e i s s t r o n g evidence t h a t t h e p l o t s
s t a t e as suggested by mean f i e l d theory
corresponding t o t h e non c r y s t a l l i n e s t a t e do n o t
~h~~
l i e on t h e curve expected from e x t r a p o l a t i o n o f the
l i q u i d s t a t e ; i t seems probable t h a t t h i s occur-
REFERENCES
rence stems from a more o r l e s s r e l a x e d s t r u c t u r e
[I]
YOUNG, W . H., Third International Conference
i n these amorphous f i l m s , which s u f f e r no annealing
s i n c e they are observed t o be unstable on heating.
on Liquid Metals, B r i s t o l 1976.
Solid S t a t e Physics 30
[ 2 ] CARGILL 111, G . S.,
Advances i n research and appzication (Academic
CONCLUSION
We s t r o v e t o perform experiments on pure me-
Press, London 1975).
[ 3 ] BIZID, A.,
BzZZ.
t a l s s i n c e we a r e concerned w i t h o n l y one k i n d o f
atom so t h a t d a t a r e d u c t i o n and s t r u c t u r a l r e s u l t s
[ 5 ] BOSIO,L.,
v i o u r we a t t r i b u t e d t o t h e p r e p a r a t i o n mode of t h e
amorphous f i l m s : i t i s p o s s i b l e t o assume t h a t a l l
non c r y s t a l l i n e metals m i g h t e x h i b i t a hard sphere
s t r u c t u r e i f , i n vapour d e p o s i t i o n , atoms reach a
cooled s u b s t r a t e w i t h no i n i t i a l k i n e t i c energy.
SEGAUD, C.,
9.
(1975)
J . Chem.Phys.
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[ 8 ] BIZID, A.,
[lo]
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[7] SCHNEIDER, T., BROUT, R.,
has q u i t e i d e n t i c a l temperature dependence. I n t h e
non c r y s t a l l i n e s t a t e , Hg shows a d i s t i n c t beha-
CORTES, R.,
[ 6 ] BERERHI, A.,
i n these p a r t i c u l a r metals, t h e d i s t o r t e d s t r u c t u r e
f a c t o r whose e x p l a n a t i o n gave r i s e t o many attempts,
23
71 (1979) 3595.
-
s i z e d t h e s i m i l a r i t i e s between t h e l i q u i d s t r u c t u r e
and the f u r t h e r c r y s t a l l i n e phase i n Ga, B i and Hg;
100 (1977)
Acta Met.
1215.
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from experiments o r from modelling. We o n l y empha-
Soc. Mineral. C~vistaZZog.
[ 4 ] RASMUSSEN, D., LOPER, C.,
are e a s i e r t o handle. We have no p l a c e here e i t h e r
t o d e t a i l t h e experimental procedure o r t o describe
BOSIO, L., CORTES, R., DEFRAIN, A.,
J . Phys.
3 (1978)
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AVERBACH, B.L.,
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[ll]
1,14C;NER, C.N. J., Third Tnternationa? Confel~ence
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