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Glass formation and crystallization in the GeSe2-GeTe-Sb2Te3 system
Thermochimica Acta, 133 (1988) 287-292 Elsevier Science Publishers B.V., Amsterdam
GLASS
FORMATIOB
AND CRYSTALLIZATIOB
S. SURIffACHI, M.D. BARON, 1 Departament
de Ffsica,
de Barcelona, 2 Departament
Facultat
de Clencies,
08193-Bellaterra,
Diagonal
III THE GeSe2-GeTe-Sb2Te3
W.T. CLAVAGUBRA-MORAl
d'Estructura
de Flsica,
287
and B. CLAVAGUBRA' Universitat
Autonoma
Spain
i Constituents
647,
SYSTEM
de la Materia,
08028-Barcelona,
Facultat
Spain
ABSTRACT
The
glass
GeSe2-GeTe-Sb2Te.8 differential
molten
scanning
forming
region
deduced.
The
process
and
formation
for
calorimetry
effective
compositions
parameters
that
of
the
type
of
the
of
glass
The
was
crystallization
that characterize former8
means
of 103 K/min
were analysed
best glass
the
by
diffraction.
of the order energy
activation
water-quenched
of
investigated
and X-ray
rate
All the results
empirical
It is concluded
was
alloys
a cooling
was obtained.
the current
crystallization
in the light glass
In
of
formation.
that system
are
IBTRODUCTIOK
As there
no absolute
is
parameters
are extensively
of the glass related reduced
to
forming the
glass
respectively takes
a value
Ill. Another
ability
equilibrium temperature,
the glass of about parameter,
for glass
criterium used
formation,
for quantitative
of molten phase
diagram.
Tgl=Tg/T1,
transition
alloys.
introduced
characterization
Some
T
and the liquidue
by
Hruby
parameters
One of
where
2/3 for a large number
of
empirical
them and
is Tl
8 temperature.
glassy
the are Tgl
substances
C21 is Kg1 defined
Thermal Analysis Proc. 9th ICTA Congress, Jerusalem, Israel, 21-25 Aug. 1988 004~6031/88/$03.50 Q 1988 Elsevier Science Publishers B.V.
are
as
Kgl=
have
kinetic,
for
crystallization subsequently parameter defined
peak.
instance the
of
give
Other
the
by
a measure
would,
parameters in
by
the glass
of
to
fundamentally energy
Turnbull
I41.Another
of the
according
are
free
introduced
Uhlmann
of the onset
formers
change
liquid
developed
to
Good glass
values.
high Kg1
as
T, is the temperature
where
kinetic forming
in
the
c31
and
empirical
ability
was
ES1 as A' = kOexp(-E/RTg>
where kg
activation
E is the effective
the
pre-exponential
an Arrhenius
factor
ability.
with
geometrical
atomic
(assumed
to have
of & or In(x) will be indicative
Other
glass-forming
and
of crystallizatlan
of the rate constant
Low values
form).
energy
parameters
and
deal
atomic
size
are structural bonding
arrangement,
and
of
effects.
In this paper and
we present
crystallization
molten
alloys.
characteristic
crystallization
scanning
calorimetry
EXPERIKRNTAL
procedure
given
obtained
by water
(estimated
quenching melting
lines of 48 mol
Z GeSe
eutectlcs
transformations
the effective
glasses
c51.
activation
from
differential
the
calorimetric
shown
and
The
state
OP
the
rate at
800 K
of
10"
The glass
forming
cooling
diffraction.
compound and
is the experimentally
the binary
and
been derived
of the
by X-ray
the congruently
figure
state
elsewhere
samples
was checked
of
have
formation
AND DISCUSSION
the preparation
water-quenched K/min>
to the glass
(DSC).
RESULTS
were
related
of the structural
the glassy
of
on
behaviour
The temperatures of
energies
Details
the results
glaasy
in Fig.1 C&Se2
is roughly
and
the
30 mol X Sb*Te3, determined
of the systems
eutectlc GeS--GeTe
limited
by
equicomposition
Also shown valley and
region
in
this
connecting
GeSeg-SkTea
289 There
is certntnfy
I relationship
and the microscopic it is likely The most
arrangamant
significant
of them,
studlees and spectroscopic and,
GeSe3,2,
SbpTe3
SbaSe+/2.
t&sing these
crass-linked forming
random
compositions
of atoms,
specific
that some
between
molecular
as deduced
analysis to
a
glassy
in the GeSe2-GeTe-Sb2Te3
fnsids
the dashed
lines and the limits
Figure
1
alloys
: C--->
quenching
forming
predicted
the melt
It is represented
region
for
. C--->>
exist.
distribution
may be GeSq,2r
GeSe,
and
G@T%/2 of a
fully
the resulting
glass
quasi-ternary in Pig.
section
1 by the region
of the composition
triangle,
by structural
in water
system
units
from radial
ws can guest
system.
.- G&ass
StructuraL
as the precursors
of the quaternary
region
In the Ce-Sb-Se-Te
extant,
unfts
network
forming
in the binaries,
lesser
molecular
the glass
units
eutectic
I
t-)
line
obtained
,
by
290 The
general
forming
conclusion
region
aforementioned
on
with
comparing
this
"theoretical"
la
the
experimental
one,
units
are probably
present
molecular
glass
that
In the
the
glasses
studied.
To get an estimate 1 the values
of the glass
of the temperatures
of crystallization, parameter.
the
most of the glasses crystallization
value
the effective
The values
and
and
B,
onset
the
HI
kinetics
of
of
the
161 has been used
and to estimate
formers
in
system,
the of
1 allows
103
glass are
K/min,
mol '5 GeTe and
shown
are also
to conclude
the
inside
about
of 155
x, was also estimated
for -In(X)
obtained of Table
composition
in Table
of the overlapping
energy,
of the parameter
analysis
rate
temperature
the peak method
activation
Careful
cooling
transltion
crystallization.
because
However
we present
the
~51.
the value
Therefore,
glass
of the
was hindered
exotherms.
of ln(kg)
glass.
study
ability
of the glass
reduced
The detailed
to obtain
forming
that
In Table
region alloys
1.
glass
the best
forming those
for each
for
a
with
a
12t5 mol X Sb2Te3.
CONCLUSIOBS
The glass
formation
water-quenched system
molten
the glasses
thermal
In
water
of these
the GeSe2
alloys
through glass
the use of
formers
parameter
some
by DSC
quantities the
thermal
of the system
coincide
of
activation
of
as
with those
on crystallization
the quasi-ternary
First
determined
From the values rich
behavlour
Then,
energy
and
kinetic
region
characteristic
for crystallization heating
the glass-forming
deduced deduced
the
on continuous
quasi-ternary
of
GeSe2-GeTe-Sb2Te3
all the glass-forming
was obtained.
and effective were
of
alloys
analysed.
have been
for quenching temperatures
and
was
parameters.
from the values
from the values
regime.
ability
system
of
of
studied The
of the
of the ';
best Kgi
291 Table
1 .- Temperatures
parameters Glass
for
effective
< * Hegting
composition x
Y
0
0 0
5
10 15 20 24 25 30 0 0 0 0 0 0 0 0 0 5 10 10 10 10 10 15 20 20 20 20 25 30
0 0 0 0 0 0
10 15 20 30 35 40 45 47 50 15 10 15 20 30 40 15 10 15 20 38 15 10
structural
energy
crystallization of
rate 20 K/min
667 613 563 536 526 501 497 480 650 642 637 617 608 595 585 581 579 572 552 547 542 536 527 518 507 510 515 497 485 485
crystallization
; Htuby parametet
temperatures (K) T T, g 777 725 685 652 630 593 587 545 746 764 734 725 722 710 686 674 652 701 683 682 680 645 605 652 610 603 578 552 548 531
transformations
(GeSe2)100-x-y
(T,g)w and
activation
temperatures
x.
glassy
transition
of
and kinetic samples CT,,)*;
temperatures (E);reduced
parameter
).
activatiotl energy B(kJ/g.at)
136 148 152 158 210 226 207 233 240
270 163 171 211 176 206 250 210 168 167 175 223 221 187
glass
glass forming parameters Kg1 XlogCAl Tgl A in (et-9 .656 .460 .477 .639 4.875 .578 * 628 ,648 .663 .658 .612 5.176 .651 .520 5.115 .471 .639 4.172 .608 .265 4.528 .659 .398 4.801 4.699 .692 .522 5.326 .690 .639 .694 .740 6.024 .865 .706 .721 .808 .782 .733 .704 .427 5.306 5.334 .634 .701 5.644 ,957 6.471 .665 5.068 .667 1.038 6.460 .693 .845 .633 .342 5.971 .653 7.066 .950 . 648 5.155 ,659 4.953 ,472 ,638 .278 4.339 .640 4.356 .605 .204 4.626 .600 .242 .594 .161 3.314
292 parameter. nearby
These
best
glass
of 15 mol X GeTe hgd
formers
have
a composition
in
the
12 mol %.S$Teg.
ACKBOWLBDGEMBBTS
This work was supported Cientifica
y TBcnica"
the "Comisi6n
by
(CAICYT)
project
Asesora
de
Investigaci6n
n0759/84.
REFERENCES
1 S. Sakka 2 A.
Hruby,
and J.D. Mackenzie, Czech.
3 D. Turnbull,
J. Phys.,
Contemp.
4 D.R. Uhlmann,
J. Bon-Cry&.
Sci.,
6 D.W. Henderson,
Bz
(1972)
Solids
5 (1971)
145.
1187.
&Q (1960) 473.
Phys.,
5 S. Surifiach, M.D. Barb, J. Mater.
J. Non-Cryst.
Solids,
7_ (1972) 337.
M.T. Clavaguera-Mora
and i. Clavaguera,
19 (1984) 3005. J. Non-Crlst.
Solids
30
(1979) 301.
GLASS
FORMATIOB
AND CRYSTALLIZATIOB
S. SURIffACHI, M.D. BARON, 1 Departament
de Ffsica,
de Barcelona, 2 Departament
Facultat
de Clencies,
08193-Bellaterra,
Diagonal
III THE GeSe2-GeTe-Sb2Te3
W.T. CLAVAGUBRA-MORAl
d'Estructura
de Flsica,
287
and B. CLAVAGUBRA' Universitat
Autonoma
Spain
i Constituents
647,
SYSTEM
de la Materia,
08028-Barcelona,
Facultat
Spain
ABSTRACT
The
glass
GeSe2-GeTe-Sb2Te.8 differential
molten
scanning
forming
region
deduced.
The
process
and
formation
for
calorimetry
effective
compositions
parameters
that
of
the
type
of
the
of
glass
The
was
crystallization
that characterize former8
means
of 103 K/min
were analysed
best glass
the
by
diffraction.
of the order energy
activation
water-quenched
of
investigated
and X-ray
rate
All the results
empirical
It is concluded
was
alloys
a cooling
was obtained.
the current
crystallization
in the light glass
In
of
formation.
that system
are
IBTRODUCTIOK
As there
no absolute
is
parameters
are extensively
of the glass related reduced
to
forming the
glass
respectively takes
a value
Ill. Another
ability
equilibrium temperature,
the glass of about parameter,
for glass
criterium used
formation,
for quantitative
of molten phase
diagram.
Tgl=Tg/T1,
transition
alloys.
introduced
characterization
Some
T
and the liquidue
by
Hruby
parameters
One of
where
2/3 for a large number
of
empirical
them and
is Tl
8 temperature.
glassy
the are Tgl
substances
C21 is Kg1 defined
Thermal Analysis Proc. 9th ICTA Congress, Jerusalem, Israel, 21-25 Aug. 1988 004~6031/88/$03.50 Q 1988 Elsevier Science Publishers B.V.
are
as
Kgl=
have
kinetic,
for
crystallization subsequently parameter defined
peak.
instance the
of
give
Other
the
by
a measure
would,
parameters in
by
the glass
of
to
fundamentally energy
Turnbull
I41.Another
of the
according
are
free
introduced
Uhlmann
of the onset
formers
change
liquid
developed
to
Good glass
values.
high Kg1
as
T, is the temperature
where
kinetic forming
in
the
c31
and
empirical
ability
was
ES1 as A' = kOexp(-E/RTg>
where kg
activation
E is the effective
the
pre-exponential
an Arrhenius
factor
ability.
with
geometrical
atomic
(assumed
to have
of & or In(x) will be indicative
Other
glass-forming
and
of crystallizatlan
of the rate constant
Low values
form).
energy
parameters
and
deal
atomic
size
are structural bonding
arrangement,
and
of
effects.
In this paper and
we present
crystallization
molten
alloys.
characteristic
crystallization
scanning
calorimetry
EXPERIKRNTAL
procedure
given
obtained
by water
(estimated
quenching melting
lines of 48 mol
Z GeSe
eutectlcs
transformations
the effective
glasses
c51.
activation
from
differential
the
calorimetric
shown
and
The
state
OP
the
rate at
800 K
of
10"
The glass
forming
cooling
diffraction.
compound and
is the experimentally
the binary
and
been derived
of the
by X-ray
the congruently
figure
state
elsewhere
samples
was checked
of
have
formation
AND DISCUSSION
the preparation
water-quenched K/min>
to the glass
(DSC).
RESULTS
were
related
of the structural
the glassy
of
on
behaviour
The temperatures of
energies
Details
the results
glaasy
in Fig.1 C&Se2
is roughly
and
the
30 mol X Sb*Te3, determined
of the systems
eutectlc GeS--GeTe
limited
by
equicomposition
Also shown valley and
region
in
this
connecting
GeSeg-SkTea
289 There
is certntnfy
I relationship
and the microscopic it is likely The most
arrangamant
significant
of them,
studlees and spectroscopic and,
GeSe3,2,
SbpTe3
SbaSe+/2.
t&sing these
crass-linked forming
random
compositions
of atoms,
specific
that some
between
molecular
as deduced
analysis to
a
glassy
in the GeSe2-GeTe-Sb2Te3
fnsids
the dashed
lines and the limits
Figure
1
alloys
: C--->
quenching
forming
predicted
the melt
It is represented
region
for
. C--->>
exist.
distribution
may be GeSq,2r
GeSe,
and
G@T%/2 of a
fully
the resulting
glass
quasi-ternary in Pig.
section
1 by the region
of the composition
triangle,
by structural
in water
system
units
from radial
ws can guest
system.
.- G&ass
StructuraL
as the precursors
of the quaternary
region
In the Ce-Sb-Se-Te
extant,
unfts
network
forming
in the binaries,
lesser
molecular
the glass
units
eutectic
I
t-)
line
obtained
,
by
290 The
general
forming
conclusion
region
aforementioned
on
with
comparing
this
"theoretical"
la
the
experimental
one,
units
are probably
present
molecular
glass
that
In the
the
glasses
studied.
To get an estimate 1 the values
of the glass
of the temperatures
of crystallization, parameter.
the
most of the glasses crystallization
value
the effective
The values
and
and
B,
onset
the
HI
kinetics
of
of
the
161 has been used
and to estimate
formers
in
system,
the of
1 allows
103
glass are
K/min,
mol '5 GeTe and
shown
are also
to conclude
the
inside
about
of 155
x, was also estimated
for -In(X)
obtained of Table
composition
in Table
of the overlapping
energy,
of the parameter
analysis
rate
temperature
the peak method
activation
Careful
cooling
transltion
crystallization.
because
However
we present
the
~51.
the value
Therefore,
glass
of the
was hindered
exotherms.
of ln(kg)
glass.
study
ability
of the glass
reduced
The detailed
to obtain
forming
that
In Table
region alloys
1.
glass
the best
forming those
for each
for
a
with
a
12t5 mol X Sb2Te3.
CONCLUSIOBS
The glass
formation
water-quenched system
molten
the glasses
thermal
In
water
of these
the GeSe2
alloys
through glass
the use of
formers
parameter
some
by DSC
quantities the
thermal
of the system
coincide
of
activation
of
as
with those
on crystallization
the quasi-ternary
First
determined
From the values rich
behavlour
Then,
energy
and
kinetic
region
characteristic
for crystallization heating
the glass-forming
deduced deduced
the
on continuous
quasi-ternary
of
GeSe2-GeTe-Sb2Te3
all the glass-forming
was obtained.
and effective were
of
alloys
analysed.
have been
for quenching temperatures
and
was
parameters.
from the values
from the values
regime.
ability
system
of
of
studied The
of the
of the ';
best Kgi
291 Table
1 .- Temperatures
parameters Glass
for
effective
< * Hegting
composition x
Y
0
0 0
5
10 15 20 24 25 30 0 0 0 0 0 0 0 0 0 5 10 10 10 10 10 15 20 20 20 20 25 30
0 0 0 0 0 0
10 15 20 30 35 40 45 47 50 15 10 15 20 30 40 15 10 15 20 38 15 10
structural
energy
crystallization of
rate 20 K/min
667 613 563 536 526 501 497 480 650 642 637 617 608 595 585 581 579 572 552 547 542 536 527 518 507 510 515 497 485 485
crystallization
; Htuby parametet
temperatures (K) T T, g 777 725 685 652 630 593 587 545 746 764 734 725 722 710 686 674 652 701 683 682 680 645 605 652 610 603 578 552 548 531
transformations
(GeSe2)100-x-y
(T,g)w and
activation
temperatures
x.
glassy
transition
of
and kinetic samples CT,,)*;
temperatures (E);reduced
parameter
).
activatiotl energy B(kJ/g.at)
136 148 152 158 210 226 207 233 240
270 163 171 211 176 206 250 210 168 167 175 223 221 187
glass
glass forming parameters Kg1 XlogCAl Tgl A in (et-9 .656 .460 .477 .639 4.875 .578 * 628 ,648 .663 .658 .612 5.176 .651 .520 5.115 .471 .639 4.172 .608 .265 4.528 .659 .398 4.801 4.699 .692 .522 5.326 .690 .639 .694 .740 6.024 .865 .706 .721 .808 .782 .733 .704 .427 5.306 5.334 .634 .701 5.644 ,957 6.471 .665 5.068 .667 1.038 6.460 .693 .845 .633 .342 5.971 .653 7.066 .950 . 648 5.155 ,659 4.953 ,472 ,638 .278 4.339 .640 4.356 .605 .204 4.626 .600 .242 .594 .161 3.314
292 parameter. nearby
These
best
glass
of 15 mol X GeTe hgd
formers
have
a composition
in
the
12 mol %.S$Teg.
ACKBOWLBDGEMBBTS
This work was supported Cientifica
y TBcnica"
the "Comisi6n
by
(CAICYT)
project
Asesora
de
Investigaci6n
n0759/84.
REFERENCES
1 S. Sakka 2 A.
Hruby,
and J.D. Mackenzie, Czech.
3 D. Turnbull,
J. Phys.,
Contemp.
4 D.R. Uhlmann,
J. Bon-Cry&.
Sci.,
6 D.W. Henderson,
Bz
(1972)
Solids
5 (1971)
145.
1187.
&Q (1960) 473.
Phys.,
5 S. Surifiach, M.D. Barb, J. Mater.
J. Non-Cryst.
Solids,
7_ (1972) 337.
M.T. Clavaguera-Mora
and i. Clavaguera,
19 (1984) 3005. J. Non-Crlst.
Solids
30
(1979) 301.