particles were tetragonal. The
enhanced tetragonality was also confirmed by the DSC results, a curie transition at
133ºC, as shown in Fig. 15. Before the NMP treatment, the barium titanate particles were
cubic at room temperature and showed no phase transformation in DSC upon heating up
to 200ºC.
46
35
40
45
50
55
0
200
400
600
800
1000
1200
1400
1600
NMP treated BT
BT
A
rb
it
ra
ry
u
n
it
s
Degree (2 Theta)
Fig. 14. Partial XRD pattern of BT – before and after NMP treatment (NMP treatment
showing the peak split at 45º)
47
The hydroxyl content in the as-received, aged and NMP treated barium titanate
particles was determined by FTIR analysis and TGA. Fig. 16
shows the FTIR spectrum
of NMP treated barium titanate along with the untreated powder. The intensity of this
broad peak in the range of 2600 - 3600 cm
-1
, which is assigned to the OH stretching
vibration, was significantly reduced after the NMP treatment. The presence of some
barium carbonate was also detected in as-received powders, which was also removed by
the treatment. It is necessary to distinguish lattice hydroxyls from the naturally absorbed
surface water because surface water does not cause lattice strain
.
The semi quantitative
comparison of the band intensities show that the lattice OH content in this NMP treated
barium titanate powder to be 0.35%.
48
90
100
110
120
130
140
150
160
170
-0.85
-0.80
-0.75
-0.70
-0.65
-0.60
-0.55
-0.50
-0.45
H
e
a
t
fl
o
w
(
w
/g
)
Temperature (degree celcius)
Fig. 15. DSC curve showing the tetragonal-to-cubic transition in the NMP treated barium
titanate powder during the process of increasing the temperature
49
4500 4000 3500 3000 2500 2000 1500 1000
500
0
-0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
NMP treated powder
As-recd. powder
A
b
s
o
rb
a
n
c
e
Wavenumbers (cm-1)
Fig. 16. FTIR spectra of barium titanate – before and after NMP treatment showing the
OH vibration at 2600 – 3600 cm
-1
50
FTIR spectra, in the OH stretching region, of hydrothermal
barium titanate powder
calcined in air for 24 hr at room temperature, 200 and 1100 °C are shown in Fig. 17. The
broad spectrum attributable to OH groups decreases with increasing the calcining
temperature. The spectrum of the BT powder aged in different pH waters has two sharp
peaks, a larger peak at 3496 cm
−1
corresponding to the surface OH and a smaller peak at
2931 cm
−1
that corresponds to the peak position observed for the lattice OH, of 1426 and
1469 cm
-1
to lattice and surface carbonate respectively and of 785 and 545 cm
-1
to barium
titanate.
Semi quantitative comparison of the species by band intensity of OH at 2931 cm
-1
was calculated to the ratio of the species by band intensity of barium titanate at 545 cm
-1
.
The observed lattice OH content in both the different pH waters is tabulated in Table 2.
The TGA results obtained were analyzed for the weight loss in each sample. It is
generally considered that the total weight loss as a combination of weight loss of
hydroxyl ions, both surface and lattice, and carbonate ions. Based on these results, a
study is being done on the TGA curves, shown in Fig. 18, for the exact temperature range
and the amount of weight loss of the lattice OH content.
It was already mentioned that between the temperature 250 – 450ºC, the
incorporated lattice hydroxyl ion diffuses to the surface [80]. Hence, at that particular
temperature range the slope and the weight loss are being calculated and the results are
tabulated in Table 3.
It is clearly evident that as the temperature increases the amount of water and
hydroxyl groups deplete. Both the results from FTIR and TGA support the earlier
statement.
51
Fig. 17a. FTIR spectra of calcined barium titanate aged in acidic water
52
Fig. 17b. FTIR spectra of calcined barium titanate aged in basic water
53
Table 2. Amount of lattice OH content with respect to temperature aged in acidic and
basic waters based on FTIR analysis.
Acidic water
Basic water
RT
0.733 %
RT
2.213 %
200 ºC
0.599 %
200 ºC
2.022 %
1100 ºC
0.125 %
1100 ºC
0.385 %
Now it is very much understood that lattice OH plays an important role in phase
transformation of barium titanate. The effect of the lattice OH content can be more
clearly estimated by performing a dielectric study on the NMP treated barium titanate as
well as the samples aged in different pH waters.
Dielectric constant values of the different samples were calculated from the
measured capacitance data using the equation 12. The dielectric constant and loss values
of the NMP treated barium titanate powder particles obtained by using castor oil as the
binder phase is plotted in Fig. 19 and extrapolating this plot gives the dielectric constant
of the NMP treated ceramic particles as 291 and the dielectric loss factor to be 0.03.
Using the same technique, the dielectric constant value of the as-received powder
particles is found to be 177 that were reported by our earlier work [53]. The dielectric
constant of the commercial tetragonal powder particles, BT 219-6, in as-received
condition is determined as 306 using the same procedure that was followed in our
previous work [53,54].
54
96
96.5
97
97.5
98
98.5
99
99.5
100
100.5
0
200
400
600
800
1000
Temperature
W
e
ig
h
t
lo
s
s
%
1100
RT
200
Fig. 18a. TGA curves for barium titanate aged in acidic water
96.5
97
97.5
98
98.5
99
99.5
100
100.5
0
200
400
600
800
1000
Temperature
W
e
ig
h
t
lo
s
s
%
1100
RT
200
Fig. 18b. TGA curves of barium titanate aged in basic water
55
Table 3. Amount of lattice OH content with respect to temperature aged in acidic and
basic waters based on TGA results.
Acidic water
Basic water
RT
0.602 %
RT
1.989 %
200 ºC
0.577 %
200 ºC
1.887 %
1100 ºC
0.183 %
1100 ºC
0.312 %
Similarly the dielectric constants of all the six samples that were aged in different
pH waters were being determined using castor oil as the binder phase. Then the dielectric
constant results were plotted against temperature and lattice OH content that are shown in
Fig. 20 and Fig. 21 respectively. The dielectric constant values of samples aged in acidic
water give higher values due to smaller amount of OH content present in them when
compared to the samples aged in basic water. The loss factor for both acidic and basic
waters was increased by a very small amount. It was observed that there was an excess
weight loss in the powder aged in basic water. The reason for this behavior was the
instability on the surface of the particle. There was a definite amount of carbonate as well
as OH present on the surface when compared to the powder aged in acidic water.
56
10
20
30
40
50
40
60
80
100
120
D
ie
le
c
tr
ic
c
o
n
s
ta
n
t
Ceramic volume%
Fig. 19. Dielectric constant values of NMP treated barium titanate vs. ceramic volume %
57
0
200
400
600
800
1000
1200
160
180
200
220
240
260
280
300
D
ie
le
c
tr
ic
c
o
n
s
ta
n
t
Temperature C
Fig. 20a. Dielectric constant values of barium titanate aged in acidic water as a function
of calcining temperature
58
0
200
400
600
800
1000
1200
160
180
200
220
240
260
280
300
D
ie
le
c
tr
ic
c
o
n
s
ta
n
t
Temperature C
Fig. 20b. Dielectric constant values of barium titanate aged in basic water as a function
of calcining temperature
59
0.1
0.2
0.3
0.4
0.5
0.6
0.7
160
180
200
220
240
260
280
OH content (%)
D
ie
le
ct
ri
c
co
n
st
a
n
t
0.00
0.05
0.10
0.15
0.20
0.25
L
o
ss
fa
ct
o
r
Fig. 21a. Dielectric properties of barium titanate aged in acidic water with increasing OH
content
60
0.0
0.5
1.0
1.5
2.0
2.5
140
160
180
200
220
240
260
OH content (%)
D
ie
le
c
tr
ic
c
o
n
s
ta
n
t
0.00
0.05
0.10
0.15
0.20
0.25
L
o
s
s
fa
c
to
r
Fig. 21b. Dielectric properties of barium titanate aged in basic water with increasing OH
content
61
The summary of the results is tabulated in Table 4.
Table 4. Variations in OH content, dielectric constant and dielectric loss values with
respect to different pH treatments of barium titanate powder.
BT treatments
Calcined
temperature
Lattice
OH %
Dielectric
constant (K)
Loss
factor
% increase in K
of NMP treated
powder (291)
25
0.67
162
0.05
44
200
0.58
180
0.04
38
Acidic water
1100
0.15
273
0.03
6
25
2.1
156
0.05
46
200
1.9
170
0.05
41
Basic water
1100
0.35
258
0.04
11
Conclusions
Barium titanate treated with NMP contains a lower concentration of lattice
hydroxyl group, resulting in a small lattice strain. The tetragonality in the hydrothermal
barium titanate particles is restored by a one-step chemical treatment. The lattice
hydroxyls in barium titanate were effectively extracted by the NMP treatment. As
hypothesized, the lattice hydroxyl release is the reason of the tetragonality recovery. This
method can be considered as a complementary treatment to promote the phase transition
of cubic barium titanate and to synthesize tetragonal ferroelectric nanoparticles.
62
XRD confirms the tetragonality with the peak split at 45º and c/a ratio is obtained
as 1.0078. FTIR investigations of hydrothermal barium titanate particles revealed a
spectrum with a broad OH band in the wave number range of 2600 - 3600 cm
−1
,
indicating the presence of a significant concentration of surface OH groups in the film. A
sharply-defined peak at 2931 cm
−1
, attributed to lattice OH species, was also found. The
apparent amount of lattice OH content was reported to be 0.35% for barium titanate
powder treated with NMP at 200ºC for 24 hr. The simulation experiment adds value to
the above statement as barium titanate calcined at 1100ºC in both acidic and basic waters
show similar values which clearly indicates that elimination of OH initiates the
tetragonality in a cubic barium titanate. Dielectric studies provide strong evidence to the
hypothesis made as the dielectric constant of NMP treated barium titanate powder
particle is 291, 64% higher than the value of as-received barium titanate, 177 and the loss
factor was observed to constant at 0.03. Hence, extraction of hydroxyl ions, in particular
the lattice OH, increases the dielectric constant of the powder.
63
REFERENCES
1.
D. C. Dube and S. J. Jang, Proc. Symp. Ceram. Dielectr. 8 (1985) 315.
2.
D. Pozar, Microwave Engg. (Addison-Wesley, Massachusetts, 1990) 313.
3.
S. K. Bhattacharya and R. R. Tummala,
J. Mater. Sci. Mater. Electron.
11
(2000)
253.
4.
Y. Rao, S. Ogitani, P. Kohl and C. P. Wong, Proc. Elec. Components and
Technology. (2000) 183.
5.
B. A. Schutzberg, C. Huang, S. Ramesh and E. P. Giannelis, Proc. Elec.
Components and Technology. (2000) 1564.
6.
S. Ogitani, S. A. Bidstrup-Allen and P. A. Kohl, IEEE Trans. Advanced
Packaging
23
(2000) 313.
7.
S. D. Cho, S. Y. Lee, J. G. Hyun and K. W. Paik, Mat. Sci. Eng. B110
(2004)
233.
8.
S. D. Cho, S. Y. Lee, J. G. Hyun and K. W. Paik, Mat. Sci: Elec. 16 (2005) 77.
9.
N. G. Devaraju, B. I. Lee, E. S. Kim, Microelec. Engg. 82 (2005) 71.
10.
T. Yamada, T. Ueda and T. Kitayama, J. Appl. Phys
.
53
(1982) 4328.
11.
N. Jayasundere and B. V. Smith, ibid
.
73
(1993) 2462.
12.
K. Mazur,
Plast. Eng.
28
(1995) 539.
13.
J. C. Maxwell-Garnett, Philos. Trans. R. Soc. London Ser. A, 203 (1904) 385.
14.
D. K. Dasgupta and K. Doughty, Thin Solid Films, 158 (1988) 93.
15.
D. Stauffer, A. Aharony, Introduction to percolation theory. Taylor & Francis,
1991.
16.
M. Sahimi, Application of percolation theory. Taylor & Francis, 1994.
17.
B. Sareni, L. Krahenbuhl, and A. Beroual, J. Appl. Phys
.
, 85 (1997) 2375.
18.
G. W. Milton, J. Appl. Phys
.
, 52 (1981) 5286.
64
19.
R. Waser, Integr. Ferroelectr. 15
(1997) 39.
20.
G. Arlt, D. Henning and G. De With, ibid. 58
(1985) 1619.
21.
S. Wada, H. Yasuno, T. Hoshina, S-M. Nam, H. Kakemoto, T. Tsurumi, Jpn. J.
Appl. Phys. 42 (2003) 6188.
22.
Y. Rao, J. Qu, T. Marinis, IEEE Trans. Components and Packaging Tech., 23
(2000) 680.
23.
G. Arlt, J. Mat. Sci. 25 (1990) 2655.
24.
D. H. Kuo, C. C. Chang, T. Y. Su, W. K. Wang and B.Y. Lin, Mat. Chem. & Phy.
85 (2004) 201.
25.
D. Sinha and P. K. C. Pillai, J. Mat. Sci. Lett
.
, 8 (1989) 673.
26.
B. I. Lee, X. Wang, S. J. Kwon, H. Maie, R. Kota, J. H. Hwang, J.G. Park, M.
Hu., Microelec. Engg. 83 (2006) 463.
27.
Y. Rao, C. P. Wong, J. Qu, IEEE Trans. Electronic Components & Tech.
Conference, (2000) 615.
28.
S. K.Bhattacharya, P. M. Raj, D. Balaraman, H. Windlass, R. R. Tummala,
Circuit World, 30/1 (2003) 31.
29.
R. N. Das, M. D. Poliks, J. M. Lauffer, V. R. Markovich, “High Capacitance,
Large Area, Thin Film, Nanocomposite Based Embedded Capacitors”
30. W. Hitesh, R. P. Markondeya, D. Balaraman, S. K. Bhattacharya, R. Tummala,
IEEE Trans. Electron. Pack. Man. 26 (2003) 2.
31. Y. Rao, A. Takahashi, C. P. Wong, Composites: A 34 (2003) 1113
32. J. Andresakis, T. Yamamoto, N. Biunno, Circuit World 30/1 (2003) 36
33. S. Ogitani, A. S. Bidstrup, P. Kohl, IPC conf., San Diego, (2000)
34. S. D. Cho, J. Y. Lee, K. W. Paik, Electron. Compon. Technol. Conference (2002)
504
35. N. Manish, A. C. Jeanine, S. Lawrence Jr., A. Sen., Chem.Mater. 3 (1991) 201
36. N. Halder, S. A. Das, S. K. Khan, A. Sen, H. S. Maiti, Mater. Res. Bull. 34 (1999)
545
65
37. R. Chen, X. Wang, Z. Gui, L. Ti, J.Am. Ceram. Soc, 86 (2003) 1022
38. C. Pecharroman, J. S. Moya, Adv. Mater. 12 (2000) 294
39. C. W. Nan, Prog. Mater. Sci. 37 (1993) 1
40. C. W. Nan, Phys. Rev. B 63 (2001) 176201
41. D. A. G. Bruggeman, Ann. Phys. (Leipzig) 24 (1935) 636
42. N. Jayasundere, B.V. Smith, J. Apl. Phy. 34 (1995) 6149
43. C. Pecharroman, B. F. Esteban, J. S. Moya, Adv. Mater. 13 (2001) 1541
44. J. J. Wu, D. S. McLachlan, Phys. Rev. B 56 (1997) 1236
45. J. J. Wu, D. S. McLachlan, Phys. Rev. B 58 (1998) 14880
46. C. Brosseau, J. Appl. Phys. 91 (2002) 3197
47. Y. Rao, C. P. Wong, IEEE Proc. Electron. Compon. Technol. Conf. (2002) 920
48. Z. M. Dang, Y. H. Lin, C. W. Nan, Adv. Mater. 15 (2003) 1625
49. Z. M. Dang, Y. Shen, C. W. Nan, Appl. Phys. Lett. 81(2002) 4814
50. D. Stauffer, Phys. Reports 54 (1979) 1
51. N. R. Jana and X. G. Peng, J. Am. Chem. Soc. 125 (2003) 14280
52. S. H. Chen, K. Kimura, Langmuir 15 (1999) 1075-1082.
53. B. I. Lee, X. Wang, S. J. Kwon, H. Maie, R. Kota, J. H. Hwang, J. G. Park, M.
Hu., Microelectron. Eng. 83 (2006) 463.
54. R. Kota, A. F. Ali, B. I. Lee, M. M. Sychov, Microelectron. Eng. (submitted)
55. Lai Qi, Synthesis and dielectric properties of ceramic-metal-polymer nano
composites
56. S. Li, J. A. Eastman, Z. Li, C.M. Foster, R. E. Newnham, L. E. Cross, Phys. Lett.
A (1996) 212, 341.
57. C. L. Wang, S. R.P. Smith, J. Phys.: Condens. Matter. 7 (1995) 7163.
58. B. Jiang, L. A. Bursill, Phys. Rev. B 60 (1999) 9978.
66
59. W. L. Zhong, Y. G. Wang, P. L. Zhang , B. D. Qu, Phys. Rev. B 50 (1994) 698.
60. H. Huang, C. Q. Sun, P. Hing, J. Phys.: Condens. Matter. 12 (2000) L127.
61. M. A. Pena, J. L. G. Fierro, Chem. Rev. 101 (2001) 1981.
62. A. S. Bhella, R. Guo, R. Roy, Mater. Res. Innovations, 4 (2000) 3.
63. P. K. Dutta, R. Asiaie, S. K. Akbar, W. Zhu, Chem. Mater. 6 (1994) 1542.
64. P. Duran, D. Gutierrez, J. Tartaj, C. Moure, Ceram. Int. 28 (2002) 283.
65. P. R. Arya, P. Jha, A. K. Ganguli, J. Mater. Chem.13 ( 2003) 415.
66. S. Bhattacharya, R. Tummalla, J. Mater. Sci. Mater. Electronics 11 (2000) 253.
67. D. H. Yoon, B. I. Lee, J. Ceram. Process. Res. 3 (2002) 41.
68. C. D. Chandler, C. Roger, M. H. Smith, J. Chem. Rev. 93 (1993) 1205.
69. D. Henning, M. Klee, W. Waser, Adv. Mater. 3 (1991) 334.
70. G. Arlt, D. Hennings, G. de With, J. Appl. Phys. 58 (1985) 1619.
71. I. J. Clark, T. Takeuchi, N. Ohtori, D. C. Sinclair, J. Mater. Chem. 9 (1999) 83.
72. S. Schlag, H. F. Eicke, Solid State Commun. 91 (1994) 883.
73. K. Ishikawa, K. Yoshikawa, N. Okada, Phys. Rev. B 37 (1988) 5852.
74. Y. Kobayashi, A Nishikata, T. Tanase, M. Konno, J. Sol-Gel Sci. Technol. 29
(2004) 49.
75. T. Takeuchi, M. Tabuchi, K. Ado, K. Honjo, O. Nakamura, H. Kageyama, Y.
Suyama, N. Ohtori, M. Nagasawa, J. Mater. Sci. 32 (1997) 4053.
76. L. Qi, B.I. Lee, P. Badheka, D. H. Yoon, W. D. Samuels, G. J. Exarhos, J. Eur.
Ceram. Soc. 24 (2004) 3553.
77. L. Qi, B. I. Lee, P. Badheka, L.Q Wang, P Gilmour, W. D. Samuels, G. J.
Exarhos, Mater. Lett. 59 (2005) 2794.
78. D. Hennings and S. Shreinmacher, J. Eur. Ceram. Soc. 9 (1992) 41.
79. S. Wada, T. Suzuki, and T. Noma, J. Ceram. Soc. Jpn. 103 (1995) 1220.
80. T. Noma, S. Wada, M. Yano, and T. Suzuki, J. Appl. Phys. 80 (1996) 5223.
67
81. D. F. K. Hennings, C. Metzmacher, and B.S. Schreinemacher, J. Am. Ceram. Soc.
84 (2001) 179.
82. A.T. Chien, L. Zhao, M. Colic, J.S. Speck, and F.F. Lange, J. Mater. Res. 14
(1999) 3330.
83. V. M. Fuenzalida, M. E. Pilleux, and I. Eisele, Vacuum 55 (1999) 81.
84. S. Wada, T. Suzuki, T. Noma, J. Ceram. Soc. Jpn. 104 (1996) 383.
85. T. Yamamoto, H. Niori, H. Moriwake, Jpn. J. Appl. Phys. 39 (2000) 5683.
86. E. Ciftci, M. N. Rahaman, J. Mater. Sci. 36 (2001) 4875
.
87. P. Badheka, L. Qi, B. I. Lee, J. Eur. Ceram. Soc.
26 (2006) 1393
88. S. K. Patil, N. Shah, F.D. Blum, M.N. Rahaman, J. Mater. Res. 12 (2005) 3312.
89. B. I. Lee, J. Electroceramics
,
3 (1999) 51
90. S. Lu, B. I. Lee, Mann, L., Mater. Lett.
,
43 (2000) 102
91. S. Lu, B. I. Lee,
Mater. Res. Bull
.,
35 (2000) 1303
92. M. H. Frey, D. A. Payne, Phys. Rev., B 54 (1996) 3158
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