R
X N Ëù m Ç ¥ ¹ Å= k KNbGeO 5 8 ý + s ÇX N Ë× D M õ m Í ¥ ¹ Å ÇÊ Ý ì Å
ö
¶ B x Ú · L |g ` @ £ · ~ ç ¡ò 6 B# Þ · »+ ä ª < · T ^ ï B# Ü · è ¡÷ 7 B) o ∗
Â
Òí ß @ / < Æ § Ó ü t o < Æõ , Ä » ^ Ó ü t$ í ½ ¨ è, Â Òí ß 609-735
»¬ £<
Â
Òí ß @ / < Æ § ¸õ < Æl Õ ü t < ÆÂ Ò, Â Òí ß 609-735 (2004¸ 4 Z 4 1{ 9 ~ Ã Î6 £ §)
KNbGeO
5Ä »o \ ¦ ] j ¸ # & ñ o õ & ñ x 9 Ä » : £ ¤$ í \ ' a # ½ ¨ % i . & ñ o õ & ñ É r \ P ì r
$ 3
© u \ ¦ s 6 x # q 1 p x : r ~ ½ Ód Ü ¼ Ð z ´+ « > % i . l & h : £ ¤$ í É r Impedance /Gain-Phase ì r$ 3 l \ ¦ s
6 x K 2
◦C/min_ 5 p x : rÖ ¦ Ð © : r \ " f 800
◦C_ : r ¸½ ¨ç ß \ " f Õ ªo ¦ Å Ò Ã º H 100 Hz ∼ 15 MHz
# 3
0 A\ " f 8 £ ¤& ñ % i . KNbGeO
5Ä »o _ & ñ o\ 9 כ ¹ô Ç Ö ¸$ í o \ -t H 8.1 eV s % i Ü ¼ 9, & ñ o l
½ ¨\ ¦ ? / H ë B6 £ § Ã º H 4 Ð+ íl q & ñ | 9 \ " f Ù þ ` ¦ Ò q t$ í " f 3 " é ¶ $ í © ` ¦ < Ê` ¦ S X % i
. Ä » : £ ¤$ í É r Ä »o s ½ ¨ç ß \ " f Ò' & ñ o ½ ¨ç ß \ 5 g " é ¶ x 9 ì r [ þ t_ Ö ¸µ 1 Ïô Ç ¹ ¡ §f e Ü ¼ Ð z ´ Ã
ºÂ Òü < ) à ºÂ Ò ¸¿ º / å L ô Ç 7 £ x \ ¦ Ð% i .
PACS numbers: 61.46, 81.10.A, 78.20.C, 81.05.K Keywords: & ñ o, ¸ & ñ , Ä »o , Ä » : £ ¤$ í
I. " e  ] Ø
ï
rî ß & ñ © I Ä »o î ß & ñ © I & ñ | 9 Ð ÷ & H õ & ñ
É
r + þ A& h 1 © s Ð+ ½ ¨ ¸& h , \ P & h , l & h o 1
p
x s à ºì ø Í÷ &# Q ª ô Ç s : r x 9 z ´+ « >` ¦ : x # K $ 3 ÷ &# Q
H 4 ¤½ + Ë& h & ³ © s . þ j H \ H ¸ & ñ \ @ /ô Ç
½
¨ l íõ < Æ x 9 6 £ x6 x " é ¶ \ " f × æ כ ¹$ í s ß ¼> Â Òy ÷ &
¦ e Ü ¼ 9 ¸ & ñ ] j ¸\ @ /ô Ç ¸§ 4 s > 5 Å q ÷ & ¦ e [1,2]. ¸ & ñ Ü ¼ Ð ½ ¨$ í ) a Ó ü t| 9 ` ¦ ë ß × ¼ H ´ òõ & h ~ ½ Ó Z O
× æ_ Ä »o _ & ñ o\ ¦ s 6 x H כ s [3].
Ù þ
Ò q t$ í õ $ í © Ü ¼ Ð s À Ò# Qt H & ñ oõ & ñ × æ \ : r ¸ü <
t
r ç ß ` ¦ ¸] X < ÊÜ ¼ Ð+ ¸ & ñ _ ß ¼l \ ¦ ] j# Q½ + É Ã º e
l M :ë H s . KNbGeO
5 H þ j H \ µ 1 Ï| ) a y © Ä » ^ s
[4]. KNbGeO
5Ä »o H & ñ oõ & ñ 1 l xî ß ¸ & ñ s + þ
A$ í ÷ & ¦ È Ò" î ô Ç © I \ ¦ Ä »t Ù ¼ Ð ¸ © I _ l & h , F
g < Æ& h : £ ¤$ í ` ¦ ½ ¨½ + É Ã º e H < É ª p Ðî r Ó ü t| 9 s [5–9].
¢
¸ô Ç KNbGeO
5 H Ä »o © I Ð ] j ¸ 6 x s ¦ © s õ
& ñ s é ß í H # \ P & h , l & h : £ ¤$ í ` ¦ ½ ¨ H X < ´ òõ
&
h s . : r ½ ¨\ " f H : r ¸\ É r & ñ o õ & ñ õ Ä » :
£
¤$ í ` ¦ ' a¹ 1 Ï % i .
∗
E-mail: [email protected]. ¸õ < Æl Õ ü t < ÆÂ Ò
II. ÷ m Ç] M öU ê s0 n É
K
2CO
3ü < Nb
2O
5\ ¦ 1 : 1 ] t q Ð ¸ ú [ O É r 6 £ § 1000
◦C
\
" f 5r ç ß 1 l xî ß 1 è ¦ 30ì r 1 l xî ß ì r Wô Ç Ê ê r
° ú É r : r ¸\ " f 5r ç ß 1 l xî ß 2 è # KNbO
3&
ñ ` ¦ ë ß [ þ t% 3 . s ì r´ ú & ñ ` ¦ GeO
2ü < 1 : 1 ] t q Ð ¸ ú [ O
# Q" f Ñ þ F K ¸m \ { É r Ê ê 1100
◦C \ " f 0 l q Ê ê ½ ¨ o
ó ø ÍÜ ¼ Ð / å LÍ t % i . ] j ¸ ) a r « Ñ_ ¿ ºa H 1.3 mm% i Ü
¼ 9 Á ºÒ oÈ Ò" î % i .
& ñ o ÷ & H õ & ñ × æ ½ ¨ ¸ o\ ¦ ' a¹ 1 Ï l 0 A # Ä » o
r « Ñ\ ¦ # Q : r ¸\ " f \ P % o ô Ç Ê ê © : r \ " f " l oÛ ¼
\
[ t s (XRD) z ´+ « >` ¦ % i . \ P r ì r$ 3 l (DSC) z ´+ « >
`
¦ : x K \ P & h : £ ¤$ í õ & ñ o õ & ñ ` ¦ ¸ % i . DSC z ´ +
« >\ " f r « Ñ6 x l H f â 5 mm, Z } s 5 mm_ Ñ þ F K6 x l
6 x ÷ &% 3 ¦ 5 p x : rÖ ¦ 2, 4, 6, 8, 10, 12
◦C/min Ü ¼ Ð 8 £ ¤
&
ñ # & ñ o\ 9 כ ¹ô Ç Ö ¸$ í o \ -t x 9 & ñ o\ ' a
>
) a ë B6 £ § Ã º\ ¦ ½ ¨ % i .
KNbGeO
5_ Ä » : £ ¤$ í ` ¦ ½ ¨ l 0 AK " f Impedance /Gain-Phase ì r$ 3 l \ ¦ 6 x % i . ¿ ºa 1.3 mm r
«
Ñ_ ª \ & h s 2.25 mm
2 F K` ¦ / B N7 £ x Ã Ì # " é ¶ + þ
A_ F G` ¦ ë ß [ þ t ¦ F K ` ¦ ² ú ¤ . ï r q ) a r « Ñ\ ¦ l
Ð\ V , # Q 5 p x : rÖ ¦ 2
◦C/min Ü ¼ Ð © : r \ 800
◦C t : r
¸\ ¦ ` ¦ o " f Ä » Ö ¦` ¦ 8 £ ¤& ñ % i . 8 £ ¤& ñ ) a Å Ò Ã º_
#
3 0 A H 100 Hz \ " f 15 MHz% i .
-495-
Fig. 1. X-ray diffraction patterns at room temperature for the samples (a) as-quenched, and after heat treatment at (b) 800
◦C (c) 900
◦C.
III. + s ÇÊ Ý õ m Í À X Ø8 ý
r
« Ñ_ ½ ¨ ¸ \ P % o : r ¸ü < r ç ß ` ¦ ² ú o < Ê\
#
Qb G> H t ' a¹ 1 Ï l 0 A # XRD 8 £ ¤& ñ ` ¦ % i .
Fig. 1 É r KNbGeO
5r « Ñ_ Ä »o © I , 800
◦C \ " f 1r ç ß , 900
◦C \ " f 1r ç ß \ P % o ô Ç Ê ê © : r \ " f 8 £ ¤& ñ ô Ç XRD Á
º] (s . \ [ t s Á º] (\ " f 4 x Ä ºo _ ì ø Í -q H כ Ü ¼
РÒ' ¸ß ¼l _ & ñ s > r F < Ê` ¦ · ú à º e [10]. s M
: r « Ñ H ¸ & ñ © ` ¦ í < Ê " f ¸ È Ò" î ô Ç © I \ ¦ Ä
»t H X < s כ É r r F g \ @ /ô Ç è ß ì ø Í & h 6 £ §` ¦ _ p
¦ ¸{ 9 ³ ð _ + þ As É r כ \ l H כ Ü
¼ Ð Ò q ty ) a .
Fig. 2 H KNbGeO
5Ä »o \ ¦ 5 p x : rÖ ¦ 2, 4, 6, 8, 10, 12
◦
C/min Ü ¼ Ð 8 £ ¤& ñ ô Ç DSC / B G s . o¶ ú ³ ð Ð · p : r
¸ H Ä »o s : r ¸(T
g) s 9 µ 1 Ï\ P 4 x Ä ºo \ ³ ðr ô Ç : r
¸ H & ñ oÖ ¦ s þ j@ / Ð ÷ & H t & h _ : r ¸s . Õ ªa Ë >\
"
f y y _ : r ¸ t _ µ 1 Ï\ P 4 x Ä ºo _ & h É r & ñ o '
& ñ ¸\ ¦ ? / 9 4 x Ä ºo _ 8 ú x & h õ _ q H s ) a
& ñ _ ^ & h q ) a . 5 p x : rÖ ¦ s 7 £ x < Ê\ Ä »o s
: r ¸ü < µ 1 Ï\ P 4 x Ä ºo _ 0 Au ¦ : r A á ¤ Ü ¼ Ð 7 £ x < Ê` ¦
^
¦ Ã º e ¦, ß ¼l ¢ ¸ô Ç & t H כ ` ¦ ^ ¦ Ã º e H X <, s
H 5 p x : rÖ ¦ s & t " f ì ø Í6 £ x s + ' Ð x 9 o H \ P & h + '% f
´
òõ ü < 5 p x : rÖ ¦ \ © ' a\ O s q & ñ | 9 © s & ñ o | ¨ c M :
Fig. 2. DSC curves on the crystallization at various heat- ing rates. The arrow indicates the glass transition tem- perature. The temperature of the maximum crystalliza- tion rate is also shown.
H \ P \ _ ô Ç 8 ú x µ 1 Ï\ P | ¾ Ós r « Ñ_ Á º> ° ú > d ¦
´ ú
» ¡ § { 9 & ñ < Ê\ " f l ô Ç .
& ñ o\ 9 כ ¹ô Ç Ö ¸$ í o \ -t x 9 & ñ o l ½ ¨\ ¦
? / H ë B6 £ § Ã º\ ¦ ½ ¨ l 0 A # \ P ì r$ 3 \ " f q 1 p x : r õ
&
ñ \ 6 x½ + É Ã º e H Ã º& ñ ) a Ozawa ~ ½ ÓZ O ` ¦ s 6 x % i .
q
1 p x : r z ´+ « >\ " f Ä »o \ ¦ { 9 & ñ ô Ç 5 p x : rÖ ¦ α Ð \ P ½ + É M : + þ
A$ í ÷ & H & ñ _ ^ & h q x H A ü < ° ú s ³ ð & ³ ) a [11].
ln α = −1.052(m/n)(E/RT )−1/n(ln(− ln(1−x)))+const (1)
#
l " f E H & ñ o\ 9 כ ¹ô Ç Ö ¸$ í o \ -t , T H : r
¸, n É r & ñ o l ½ ¨\ ¦ ? / H ë B6 £ § Ã º s 9 m É r
&
ñ _ $ í © " é ¶` ¦ · p . nõ m s _ ' a > H íl Ù þ
s > r F # & ñ o õ & ñ 1 l xî ß \ Ù þ Ò q t$ í s \ O Ü ¼ n
= m s ¦ Ù þ Ò q t$ í s e Ü ¼ n = m + 1s [11].
Fig. 3 É r & ñ o\ 9 כ ¹ô Ç Ö ¸$ í o \ -t \ ¦ ½ ¨ l 0 A K
" f : r ¸\ @ /ô Ç & h q _ o\ ¦ y y _ 5 p x : rÖ ¦ \ @ /
# Õ ª 2 ; Õ ªa Ë >s . l Ö ¦ l ÐÂ Ò' ½ ¨ô Ç Ö ¸$ í o \ -t
° ú
כ É r 8.1 eV s % 3 . Ö ¸$ í o \ -t > í ß \ " f 9 כ ¹ô Ç
&
ñ o ) a  Òx q H DSC/ B G _ þ j@ /ì ø Í6 £ x : r ¸ s _ : r ¸
Ð ] jô Ç % i . s H & ñ o / B G _ þ j@ /& h s Ê ê\ " f H
& ñ s " f Ð Ø æ[ t # $ í © ` ¦ " 3 Æ Ò ½ + Ë5 gt ¦ z · ú
â
> [ þ t_ ¸" fo \ " f & ñ s $ í © H 1 p x_ # Q t
Fig. 3. Modified Ozawa plot to get the activation energy from the slope. The symbols are measured data and the lines are from the linear fit.
´
òõ " f & ñ s { 9 & ñ > $ í © t 3 l w l M : ë
H s .
Fig. 4 H & ñ o l ½ ¨\ ¦ ? / H ë B6 £ § Ã º\ ¦ ½ ¨ l 0 AK " f # Q 5 p x : rÖ ¦ \ @ /ô Ç DSC / B G ` ¦ 2 ; Õ ªa Ë >s .
5 p
x : rÖ ¦ s Z } f \ 4 x Ä ºo ¦ : r Ü ¼ Ð s 1 l x ¦ ß ¼ l
& t H X < s H & ñ o \ P & h Ü ¼ Ð Ö ¸$ í o ÷ & H õ
&
ñ e ` ¦ Ð# ï r .
{ 9
& ñ ô Ç : r ¸\ " f_ ^ & h q \ ¦ 5 p x : rÖ ¦ \ @ /K " f ? /
#
Q ë B6 £ § à º\ ¦ ½ ¨½ + É Ã º e H X < Fig. 5\ " f ? / H ë B 6
£
§ Ã º_ ° ú כ É r # Q l Ö ¦ l ÐÂ Ò' ¨ î ç H 4±0.3_ ° ú כ` ¦ ° ú
H . s H & ñ o õ & ñ 1 l xî ß Ù þ s Ò q t$ í ÷ & 9 3 " é ¶& h
$ í
© ` ¦ < Ê` ¦ · p [11].
Fig. 6 É r Å Ò Ã º\ É r Ä » Ö ¦ z ´Ã ºÂ Òü < ) à ºÂ Ò_ : r
¸ _ > r$ í ` ¦ · p . Ä » Ö ¦ z ´Ã ºÂ Òü < ) à ºÂ Ò_ þ j@ /
&
h É r 655
◦C Ð" f DSC µ 1 Ï\ P 4 x Ä ºo _ þ j@ /& h õ q 5 p wô Ç
: r ¸\ " f è ß . Ä » Ö ¦ s 400
◦C H % \ " f 7 £ x
Fig. 4. Blow up of DSC curves on the crystallization at various heating rates.
Fig. 5. Modified Ozawa plot to get the crystallization parameter n. The symbols are measured data and the lines are from the linear fit.
#
550
◦C H % \ " f 4 x Ä ºo \ ¦ ? / H כ É r Ä »o _ ¢ - a
o & ³ © x 9 Ô ¦í HÓ ü t ´ òõ < Êa > r F H כ Ü ¼ Ð #
. Ô ¦í HÓ ü t ´ òõ H à º è, í ß è o 1 p x \ _ #
±
ú Ã º e H X < s \ @ /ô Ç ½ ¨^ & h ½ ¨ x 9 ¢ - a o & ³ © É r Æ Ò Ê
ê > 5 Å q à º' ÷ &# Q ½ + É õ ] js . 600
◦C H % _ Ä » Ö
¦ 7 £ x H Ä »o s : r ¸\ " f & h $ í É r ± ú t ¦ " é ¶ [ þ t _ Ä »1 l x ¸ H & 4 R" f ü @Â Ò l © _ o\ ¸ ú Ø Ô> ÷ &
Fig. 6. Real and imaginary parts of dielectric constant
measured with the heating rate of 2
◦C/min during the
crystallization of amorphous KNbGeO
5.
Ù
¼ Ð DSC/ B G _ 4 x Ä ºo s Ê ê\ Ä » Ö ¦ É r y è l r
ô Ç . 677
◦C s Ê ê\ H Ä » Ö ¦_ 7 £ x H & ñ
o ¢ - a y = å Qè ß s Ê ê : r ¸ © 5 p x \ É r l # \ ¦ · p
.
IV. + s Ç Â ] Ø
ª F Gó ø Í / å LÍ tZ O ` ¦ s 6 x # KNbGeO
5Ä »o \ ¦ ] j ¸
%
i . XRD, DSC\ ¦ s 6 xô Ç ½ ¨ ¸& h , \ P & h z ´+ « >` ¦ : x K KNbGeO
5Ä »o _ & ñ o l ½ ¨\ ¦ ½ ¨ % i Ü ¼ 9 Ä » : £ ¤
$ í
\ ' aô Ç ½ ¨\ ¦ Ã º' % i . XRD Á º] (\ ¦ : x K " f Ä » o
& ñ o÷ & H õ & ñ \ " f ¸ & ñ s > r F < Ê` ¦ S X ½ + É Ã
º e % 3 . \ P & h ì r$ 3 ` ¦ : x K ½ ¨ô Ç Ä »o _ & ñ o\ 9 כ
¹ô Ç \ -t H 8.1 eV s % 3 Ü ¼ 9 & ñ o l ½ ¨\ ¦ ? / H ë
B6 £ § Ã º n É r 4 Ð+ > Ù þ Ò q t$ í õ 3 " é ¶ $ í © ` ¦ < Ê` ¦ µ
1 ß+ À I . l & h : £ ¤$ í ¸ \ " f H Ä »o s : r ¸ ½ ¨ç ß Â Ò
H \ " f & h ¸_ ¢ - a o\ É r s : r_ ¹ ¡ §f e 7 £ x Ð Ä » Ö
¦_ z ´Ã ºÂ Òü < ) à ºÂ Ò ¸¿ º / å L y 7 £ x < Ê` ¦ S X
% i .
P c
p 8 ý ò k >
: r ½ ¨ H t % i | Ä Ìí ß \ O $ 3 , ~ Ã Ì ½ ¨ § 4 ª $ í \ O _
½ ¨ õ Ð Ã º' ÷ &% 3 6 £ §.
[1] T. Kawamoto and S. Abe, Phys. Rev. B 68, 235112 (2003).
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Rhee, Phys. Rev. B 68, 134416 (2003).
[3] G. H. Beal and D. A. Duke, J. Master. Sci. 4, 340 (1969).
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Komatsu, J. Appl. Phys. 94, 8 (2003).
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[6] R. Sakai, Y. Benino and T. Komatsu, Appl. phys.
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[8] K. Hirano, Y. Benino and T. Komatsu, J. Phys.
Chem. Solids 62, 2075 (2001).
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Crystallization and Dielectric Properties of Amorphous KNbGeO 5
C. H. Song, H. W. Choi, D. G. Kang, J. E. Kim, J. K. Lee and Y. S. Yang
∗Department of Physics, RCDAMP, Pusan National University, Busan 609-735
S. J. Kim
School of Nano Science and Technology, Busan 609-735 (Received 1 April 2004)
The crystallization mechanism and the dielectric property of amorphous KNbGeO
5were studied.
Differential scanning calorimetry was used to investigate the crystallization mechanism. The di- electric property was measured by using an impedance/gain-phase analyzer in the frequency range 100 Hz ∼ 15 MHz with the heating rate of 2
◦C/min. Crystallization was found to occur through a 3-dimensional growth with an activation energy of 8.1 eV and a crystallization parameter of 4.
There was an abrupt increase in both the real and the imaginary parts of the dielectric constant for glass in the crystal transition region due to the active motions of atoms and molecules.
PACS numbers: 61.46, 81.10.A, 78.20.C, 81.05.K
Keywords: Crystallization, Nanocrystal, Dielectric property
∗