Effect of B2O3-Bi2O3-SiO2-ZnO glass on the sintering and microwave dielectric properties of...

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Effect of B2O3-Bi2O3-SiO2-ZnO glass on the sintering and

microwave dielectric properties of 0.83ZnAl2O4-0.17TiO2

Sherin Thomas, Mailadil Thomas Sebastian *

Materials and Minerals Division, National Institute for Interdisciplinary Science and Technology, Trivandrum 695019, India

Received 25 November 2006; received in revised form 26 April 2007; accepted 3 May 2007

Available online 16 May 2007

Abstract

The 0.83ZnAl2O4-0.17TiO2 (ZAT) ceramics were synthesized by solid state ceramic route. The effect of 27B2O3-35Bi2O3-

6SiO2-32ZnO (BBSZ) glass on the microwave dielectric properties of ZAT was investigated. The crystal structure and the

microstructure of the ceramic-glass composites were studied by X-ray diffraction and scanning electron microscopic techniques.

The low frequency dielectric loss was measured at 1 MHz. The dielectric properties of the sintered samples were measured in the

microwave frequency range by the resonance method. Addition of 0.2 wt% of BBSZ improved the dielectric properties with quality

factor (Qu � f) > 120,000 GHz, temperature coefficient of resonant frequency (tf) = �7.3 ppm/8C and dielectric constant

(er) = 11.7. Addition of 10 wt% of BBSZ lowered the sintering temperature to about 950 8C with Qu � f > 10,000 GHz,

er = 10 and tf = �23 ppm/8C. The reactivity of 10 wt% BBSZ added ZAT with silver was also studied. The results show that

ZAT doped with suitable amount of BBSZ glass is a possible material for low-temperature co-fired ceramic (LTCC) application.

# 2007 Elsevier Ltd. All rights reserved.

Keywords: A. Ceramics; A. Glasses; B. Dielectric properties; C. Electron microscopy; C. X-ray diffraction

1. Introduction

The low er and low loss dielectrics play a vital role in the microelectronic industry, as they are suitable for substrate

and packaging applications [1,2]. Low loss, low er substrates are used in printed wiring boards (PWB), central

processing units, wireless access circuits, LAN’s, optical communications, etc. The rapid development in the

electronic industry paved way for low-temperature co-fired ceramic (LTCC) technology for substrate materials. The

important characteristics required for a packaging material are: (i) low dielectric constant er < 10 (to increase the

signal speed), (ii) low dielectric loss or high quality factor (to increase selectivity), (iii) high thermal conductivity (to

dissipate the heat generated), (iv) low or matching coefficient of thermal expansion to that of the materials attached to

it, (v) low-temperature coefficient of resonant frequency tf [3–8]. Recently a number of new glass-ceramic composites

with low permittivity have been developed for LTCC applications [9–12]. In multilayer structure, it is necessary to

lower the sintering temperature of the dielectrics below 950 8C in order to co-fire with low melting and highly

conducting internal electrodes, such as Ag [7,13–15]. The ability to integrate high performance passive components,

such as capacitors, filters and transmission lines into these multilayer structures make these substrates useful for RF

www.elsevier.com/locate/matresbu

Materials Research Bulletin 43 (2008) 843–851

* Corresponding author.

E-mail address: [email protected] (M.T. Sebastian).

0025-5408/$ – see front matter # 2007 Elsevier Ltd. All rights reserved.

doi:10.1016/j.materresbull.2007.05.015


applications, such as wideband code-division multiple access down converter, antennas, transmitter/receiver filter, etc.

There are three methods for reducing the sintering temperature of ceramics, such as addition of low melting glasses,

chemical processing and smaller particle size. Among these methods addition of low melting, low loss glass is the

most effective and widely accepted method despite the fact that there is a degradation in the microwave dielectric

properties [16,17].

Even though several dielectric materials with good microwave dielectric properties have been reported, most of

them have sintering temperatures above 1200 8C, which limits their use in LTCC applications. Many attempts were

made to reduce the firing temperature by the addition of various low melting and low loss glasses [16–24]. The

microwave dielectric properties of various borosilicate glasses were reported by Wu and Huang [25]. Wang et al. [23]

reported that the sintering temperature of (Zn1�x, Mgx)TiO3 can be lowered to 950 8C by the addition of ZnO-B2O3-

SiO2 glass. A new glass-ceramic composition consisting of MgAl2O4 crystals and Li-Mg-Zn-B-Si-O glass with a low

dielectric constant of 7.4, Qu � f of about 50,000 GHz but having a high negative tf of �90 ppm/8C at a temperature

less than 1000 8C has been developed [11]. Studies were also conducted on BBSZ glass for making it a suitable

additive for LTCC applications [7,26].

Spinels with general formula AB2O4 [A = Zn, Mg, Ni, Co; B = Al, Ga, Fe] form an important class of compounds

with a variety of interesting electrical, optical, mechanical and magnetic properties [27]. They belong to the face

centered cubic symmetry with space group Fd3m. The cubic cell contains a close-packed array of 32 oxygen atoms

with cations in the tetrahedral and octahedral sites. In the normal spinel structure, the divalent cations occupy the

tetrahedral sites and the trivalent cations occupy the octahedral sites [28]. The low dielectric constant and a high

Qu � f make ZnAl2O4 [29] and MgAl2O4 [30] possible candidates for packaging applications. ZnAl2O4 has a high

tf of�79 ppm/8C which precludes its use in practical applications. Recently Surendran et al. [29] studied the effect of

TiO2 on the dielectric properties of ZnAl2O4 and tuned the tf to a nearly zero value. They proposed (1 � x)ZnAl2O4-

xTiO2 [x = 0.17] as an ideal composition for substrate applications. However the sintering temperature of ZAT was

above 1400 8C which need to be reduced for LTCC applications. In the present paper we report the low-temperature

sintering of 0.83ZnAl2O4-0.17TiO2 (ZAT) ceramics through suitable glass addition.

2. Experimental

The 0.83 ZnAl2O4-0.17 TiO2 (ZAT) ceramics were prepared by the conventional solid state ceramic route. High

purity ZnO [Aldrich Chemical Company, 99.9%] and Al2O3 [Alcoa A16SG] were used as starting materials for the

synthesis of ZnAl2O4. The chemicals were stoichiometrically weighed and were ball milled in polyethylene bottle

using Zr balls in distilled water for 24 h. The slurry was dried at 100 8C in hot air oven and was calcined at 1100 8C/

4 h. It was then ball milled with anatase TiO2 according to the composition (0.83 ZnAl2O4-0.17 TiO2) for 24 h. The

slurry was dried and ground well. 4 wt% PVA was added as binder, mixed and again ground into fine powder and

pressed to form cylindrical disks of 20 mm diameter and 10 mm height under a uniaxial pressure of about 100–

150 MPa. Thin pellets of the ZAT with diameter 14 mm and thickness 1 mm were made for low frequency

measurements. For preparing 27B2O3-35Bi2O3-6SiO2-32ZnO (BBSZ) glass, calculated amount of high purity

(99.9%) oxides such as B2O3, Bi2O3, SiO2, and ZnO were weighed and mixed for 2 h in an agate mortar with pestle

using distilled water as the medium. It was dried and melted in a platinum crucible at the temperature 950 8C,

quenched and crushed into fine powder in an agate mortar. Different weight percentages of BBSZ glass was added to

the pure ZAT. Small amount of LiF [CDH Pvt. Ltd.] was also used for densification. The pellets were prepared as

described above. The pure sample was sintered at 1450 8C/4 h. The glass added samples were sintered at different

temperature ranging from 900 8C to 1450 8C/4 h.

The densities of sintered samples were measured by the Archimedes method. The crystal structure of the powdered

samples was studied using XRD patterns (CuKa radiation, Philips X-ray Diffractometer). The sintered samples were

etched at a temperature 25 8C below the sintering temperature for 30 min and the surface morphology was recorded

using Scanning Electron Microscope (JEOL-JSM 5600LV, Tokyo Japan). The thin pellets were electroded by

uniformly coating with silver paste on both sides in the form of ceramic capacitors. The low frequency (50–5 MHz)

dielectric measurements were made using an LCR meter (HIOKI 3532-50 LCR HiTESTER). The temperature

variation of dielectric constant (te) at low frequency (1 MHz) was also measured. The well-polished ceramic pellets

with an aspect ratio of 1.8–2.2, which is ideal for maximum separation of the modes, were used for microwave

measurements by the resonance method. The microwave dielectric properties of the samples were measured in the

S. Thomas, M.T. Sebastian / Materials Research Bulletin 43 (2008) 843–851844


microwave frequency range of 5–6 GHz using a vector network analyzer HP 8753 ET. The unloaded quality factor Qu

of the resonance was determined using the cavity method [31]. The samples were placed on a low loss quartz spacer to

reduce the loss due to surface resistivity of the cavity. The temperature coefficient of resonant frequency (tf) was

measured by noting the variation of the resonant frequency of TE01d mode with temperature in the range of 25–75 8C.

tf ¼1

f� D f

DT

where Df is the variation in the resonant frequency from room temperature and DT is the difference in temperature. The

dielectric constant er was measured by the post-resonator method of Hakki and Coleman [32]. The coefficient of

thermal contraction of the samples was measured using thermo mechanical analyzer (TMA-60H Shimadzu) in the

temperature range of 30–1200 8C.

3. Results and discussion

Fig. 1a shows the XRD patterns of ZAT. The powder diffraction patterns of ZnAl2O4 and TiO2 were indexed based

on JCPDS File Card Numbers 5-669 and 21-1276, respectively. The XRD pattern of ZAT shows that ZnAl2O4 did not

form a solid solution with TiO2 as reported earlier [29]. The theoretical density of ZAT measured using the mixture

rule was found to be 4.58 g/cm3. The measured density of the sample sintered at 1450 8C was 97% of the theoretical

density. Fig. 1b–e shows the XRD patterns of ZAT sintered with different weight percentages of BBSZ glass. Even

though large amount (10, 12, 15 wt%) of BBSZ glass was added to ZAT no additional peaks were observed. These

samples were sintered at 950 8C/4 h at a slow cooling rate of 3 8C/min. It is possible that the BBSZ liquid phase was

not crystallized and retained its amorphous nature. Hence, BBSZ glass existed as a liquid phase during sintering and

assisted the densification of ZAT ceramics. The theoretical density (D) of the glass added ZATwas calculated using the

equation [16].

D ¼ W1 þW2

ðW1=D1Þ þ ðW2=D2Þ

where W1 and W2 are the weight percentage of the ZAT and glass with densities D1 and D2, respectively. The relative

densities of various glass added ZAT are shown in the Table 1.

S. Thomas, M.T. Sebastian / Materials Research Bulletin 43 (2008) 843–851 845

Fig. 1. The powder diffraction patterns of (a) 0.83ZnAl2O4-0.17TiO2 (ZAT) sintered at 1450 8C, (b) ZAT + 10 wt% BBSZ sintered at 950 8C, (c)

ZAT + 12 wt% BBSZ sintered at 950 8C, (d) ZAT + 15 wt% BBSZ sintered at 950 8C and (e) ZAT + 10 wt% BBSZ + 0.3 wt% LiF sintered at

925 8C.


Figs. 2a and 3a, respectively, show the SEM and backscattered images of ZAT sintered at 1450 8C indicating that

ZnAl2O4 and TiO2 do not react to form any secondary phase [29,30]. The bigger grains correspond to ZnAl2O4 and the

smaller ones that of TiO2. Fig. 2b shows the SEM picture of ZAT doped with 0.2 wt% BBSZ. The presence of dense

grains indicates the improvement in sinterability due to liquid phase sintering (see also Table 1). Fig. 2c shows the

SEM picture of ZAT doped with 10 wt% BBSZ showing the reduction in the grain size and presence of glass. Fig. 3b

shows the backscattered electron image of the above sample. The glass did not react with ZAT but forms a glassy layer

over the grain leading to excess liquid phase formation [33]. The reduction in grain size resulted in an increase in

porosity and thereby a decrease in the density. The SEM picture of ZAT doped with 10 wt% BBSZ and 0.3 wt% LiF

(Fig. 2d) was similar to that doped with glass alone.

Table 1 shows the optimized sintering temperature and the dielectric properties of different wt% of BBSZ added

ZAT. The low frequency measurements showed that the dielectric loss decreased for small wt% of glass but the

addition of larger amounts of glass gradually increased the loss factor. The microwave dielectric properties of undoped


Table 1

The sintering temperature, relative density and dielectric properties of ZAT doped with different weight percentage of BBSZ glass

Weight % of BBSZ added Sintering temperature (8C/h) Microwave properties Loss at 1 MHz

%Density Qu � f (GHz) tf (ppm/8C) er

0 1450/4 97 91,000 1.4 11.7 0.001

0.1 1425/4 97 96,000 �4.2 11.7 0.0007

0.2 1400/4 98 120,000 �7.3 11.7 0.0004

0.5 1375/4 97 60,000 �9.4 11.6 0.0016

1 1300/4 96 49,000 �10.1 11.6 0.0019

3 1300/4 95 35,000 �13.9 11.3 0.0029

5 1150/4 95 21,000 �19.7 11.2 0.0035

10 950/10 93 12,000 �23.2 10.9 0.0058

12 950/10 93 11,500 �25.2 10.9 0.0155

15 950/10 91 9,300 �29 10.6 0.0307

10 + 0.3LiF 925/10 94 14,500 �28 10.5 0.0046

Fig. 2. The scanning electron micrographs of (a) pure ZAT, (b) doped with 0.2 wt% BBSZ sintered at 1400 8C, (c) doped with 10 wt% BBSZ

sintered at 950 8C and (d) doped with 10 wt% BBSZ and 0.3 wt% LiF sintered at 925 8C.


ZAT sintered at 1450 8C are Qu � f = 91,000 GHz, er = 11.7 and tf = 1.4 ppm/8C. The addition of 0.2 wt% BBSZ

glass improved the quality factor to nearly 120,000 GHz and tf to �7.3 ppm/8C. The density was improved slightly

(98%) due to the liquid phase formation mentioned earlier. The liquid phase surrounding the grain will provide an easy

path for atomic diffusion thus improving the density and quality factor. The sintering temperature was lowered to

1400 8C and the dielectric constant remained the same. The ZnO in BBSZ glass acts as a modifier oxide which breaks

the network structure of glass thereby lowering the softening point of the glass and increasing its fluidity. The

additional increase of solubility of ceramics with such additives increases the densification [13]. The loss factor (tan d)

of BBSZ glass is relatively low (0.001) as compared to other glasses [18]. The properties of BBSZ glass are given in

Table 2. The quality factor, dielectric constant and the sintering temperature were found to decrease with the addition

of higher wt% of BBSZ glass. The tf was found to increase to more negative value which may be attributed to the high

negative tf value of the BBSZ glass [7]. The variation of er is similar to that of the relative density. Addition of more

than 0.2 wt% of glass decreased the sintering temperature with a degradation in the quality factor. For 1 and 3 wt% of

BBSZ glass there was no change in the sintering temperature (1300 8C) but the relative density was reduced to 96%

and 95% respectively. A corresponding decrease was also noted for the quality factor and the dielectric constant as

seen from the Table 1.

Fig. 4a shows the variation of quality factor and tf with the sintering temperature for ZAT doped with 10 wt% BBSZ

glass. The quality factor increased gradually with sintering temperature upto 980 8C. However, tf also shifted to more

negative value. It was observed that at a sintering temperature of 950 8C the quality factor was about 12,000 GHz and

tf was about �23 ppm/8C. The dielectric constant was about 10.9. Further increase in the sintering temperature

increased the quality factor, and the tf was increased to more negative values. The density was decreased with

increasing amount of glass to nearly 93% as seen in Table 1. Further increase in the glass content had no effect on the

sintering temperature since BBSZ glass melts at 950 8C. Addition of large amount of glass decreases the quality factor

due to the increase in porosity (see Fig. 2c) and the fact that glass has a higher dielectric loss. The quality factor was

reduced to nearly 9300 GHz by the addition of 15 wt% BBSZ. The density was lowered to 91% with a dielectric

constant of 10.6 and with a tf of �29 ppm/8C. The low dielectric constant of the glass and the porosity decreased the

dielectric constant of the ceramic-glass composite. The tf reached a high value of nearly �30 ppm/8C. In order to

improve the densification of the material a small amount (0.3 wt%) of lithium fluoride (LiF) was added to the

composition ZAT + 10 wt% BBSZ. The variation of quality factor and tf of LiF added ZAT with sintering temperature


Fig. 3. The backscattered electron image of (a) pure ZAT and (b) doped with 10 wt% BBSZ sintered at 950 8C.

Table 2

Physical and electrical properties of BBSZ glass

Properties Value

Melting point 950 8CDensity 4.3 g/cm3

Dielectric constant 8.8

Loss at 1 MHz 0.0013


is shown in Fig. 4b. It was seen that the quality factor showed a maximum value at a temperature of 925 8C and

thereafter a steady decrease was noted. The tf showed a similar variation with the sintering temperature. The samples

sintered at 925 8C/10 h showed a Qu � f of 14,500 GHz with a tf �28 ppm/8C and er of nearly 10.5 (see Table 1).

Fig. 5a and b shows the shrinkage of ZAT + 10 wt% BBSZ and ZAT + 10 wt% BBSZ + 0.3 wt% LiF, respectively. The

sample sintered with LiF shrinks at a slightly lower temperature than that added with BBSZ glass alone. The shrinkage

was complete only beyond 1000 8C. However, sintering the samples above 925 8C decreased the quality factor as


Fig. 4. The variation of quality factor and tf with sintering temperature for ZAT doped with (a) 10 wt% BBSZ glass and (b) 10 wt% BBSZ

glass + 0.3 wt% LiF.

Fig. 5. The shrinkage curves of ZAT doped with (a) 10 wt% BBSZ and (b) 10 wt% BBSZ + 0.3 wt% LiF.



Fig. 6. The variation of dielectric constant (1 MHz) with temperature for ZAT and 10 wt% BBSZ added ZAT.

Fig. 7. The XRD pattern of 10 wt% BBSZ added ZAT treated with 20 wt% of silver.

Fig. 8. The scanning electron micrograph of ZAT doped with 10 wt% BBSZ glass and 20 wt% silver.


shown in Fig. 4b. The variation of dielectric constant (measured at 1 MHz) of ZAT and that doped with 10 wt% BBSZ

with temperature is shown in Fig. 6. It is noted that the dielectric constant remains almost a constant in the temperature

range of 20–75 8C.

In order to study the reactivity of silver with the glass added ceramics, 20 wt% Ag was added to ZAT + 10 wt%

BBSZ composition. Figs. 7 and 8 show the powder diffraction pattern and the SEM picture of the above composition,

respectively. The powder diffraction patterns of Ag were indexed based on JCPDS File Card Number 4-783. It is

evident from these figures that silver remains unreacted with the ceramic-glass composite, which is one of the

requirements of LTCC.

4. Conclusion

The effect of addition of 27B2O3-35Bi2O3-6SiO2-32ZnO (BBSZ) glass on the microwave dielectric properties of

0.83ZnAl2O4-0.17TiO2 (ZAT) is investigated. It is found that addition of a small amount of BBSZ glass improved the

quality factor. Addition of 0.2 wt% BBSZ lowered the sintering temperature to 1400 8C with quality factor (Qu � f) of

120,000 GHz, a temperature variation of resonant frequency (tf) of �7.3 ppm/8C and a dielectric constant of 11.7.

Addition of 10 wt% of BBSZ glass lowered the sintering temperature to 950 8C with Qu � f of nearly 12,000 GHz and

dielectric constant of 10.9. Addition of a small amount of LiF in addition to BBSZ can further lower the sintering

temperature to 925 8C with considerable improvement in the quality factor but with an increased negative tf. It is

found that the common electrode material silver does not react with ZAT-BBSZ composites. Thus, ZAT-BBSZ

ceramic-glass composite is a promising material for low-temperature co-fired ceramic application and as substrates for

microwave integrated circuit (MIC) or for millimeter wave communication.

Acknowledgements

The authors are grateful to the Defence Research and Development Organisation, New Delhi, India for the financial

assistance. The authors are also thankful to Dr. Parameswaran from IGCAR, Kalpakkam for recording the

backscattered images.

References

[1] R.R. Tummala, J. Am. Ceram. Soc. 74 (5) (1991) 895–908.

[2] D.D.L. Chung, Materials for Electronic Packaging, Butterworth-Heinemann, Boston, 1995, pp. 19–27.

[3] Y. Guo, H. Oshato, K. Kakimoto, J. Eur. Ceram. Soc. 26 (2006) 1827–1830.

[4] A. Stiegelschmitt, A. Roosen, C. Ziegler, S. Martius, L.-P. Schmidt, J. Eur. Ceram. Soc. 24 (2004) 1463–1466.

[5] M.M. Krzmanc, M. Valant, D. Suvorov, J. Eur. Ceram. Soc. 25 (2005) 2835–2838.

[6] M. Kono, H. Takagi, T. Tatekawa, H. Tamura, J. Eur. Ceram. Soc. 26 (2006) 1909–1912.

[7] O. Dernovsek, A. Naeini, G. Preu, W. Wersing, M. Eberstein, W.A. Schiller, J. Eur. Ceram. Soc. 21 (2001) 1693–1697.

[8] C.-S. Chen, C.-C. Chou, C.-S. Chen, I.-N. Lin, J. Eur. Ceram. Soc. 24 (2004) 1795–1798.

[9] Y.J. Seo, D.J. Shin, Y.S. Cho, J. Am. Ceram. Soc. 89 (7) (2006) 2352–2355.

[10] M.-C. Wu, K.-T. Huang, W.-F. Su, Mater. Chem. Phys. 98 (2006) 406–409.

[11] N. Mori, Y. Sugimoto, J. Harada, Y. Higuchi, J. Eur. Ceram. Soc. 26 (2006) 1925–1928.

[12] C.-S. Chen, C.-C. Chou, W.-J. Shih, K.-S. Liu, C.-S. Chen, I.-N. Lin, Mater. Chem. Phys. 79 (2003) 129–134.

[13] Y. Imanaka, Multilayered Low Temperature Cofired Ceramics (LTCC), Technology Springer, New York, 2005, pp. 23–25.

[14] H. Kagata, T. Inoue, J. Kato, T. Ishizaki, Ceram. Trans. 32 (1992) 81–90.

[15] Y. Wang, G. Zhang, J. Ma, Mater. Sci. Eng. B 94 (2002) 48–53.

[16] T. Takada, S.F. Wang, S. Yoshikawa, S.-J. Jang, R.E. Newnham, J. Am. Ceram. Soc. 77 (7) (1994) 1909–1916.

[17] T. Takada, S.F. Wang, Shoko Yoshikawa, S.-J. Jang, R.E. Newnham, J. Am. Ceram. Soc. 77 (9) (1994) 2485–2488.

[18] K.P. Surendran, P. Mohanan, M.T. Sebastian, J. Solid State Chem. 177 (2004) 4031–4046.

[19] Q.H. Yang, E.S. Kim, Y.J. Kim, P.K. Kim, Mater. Chem. Phys. 79 (2003) 236–238.

[20] Y.-W. Liu, P. Lin, Mater. Chem. Phys. 92 (2005) 98–103.

[21] H. Jantunen, R. Rautioaho, A. Uusimaki, S. Leppavuori, J. Eur. Ceram. Soc. 20 (2000) 2331–2336.

[22] J.-A. Lee, J.-H. Lee, J.-J. Kim, J. Eur. Ceram. Soc. 26 (2006) 2135–2138.

[23] Y.-R. Wang, S.-F. Wang, Y.-M. Lin, Ceram. Int. 31 (2005) 905–909.

[24] J.-M. Yoon, J.-A. Lee, J.-H. Lee, J.-J. Kim, S.-H. Cho, J. Eur. Ceram. Soc. 26 (2006) 2129–2133.

[25] J.-M. Wu, H.-L. Huang, J. Non-Cryst. Solids 260 (1999) 116–124.

[26] R. Karmazin, O. Dernovsek, N. Ilkov, W. Wersing, A. Roosen, M. Hagymasi, J. Eur. Ceram. Soc. 25 (2005) 2029–2032.



[27] H.M. Buschbaum, J. All. Comp. 349 (2003) 49–104.

[28] K.E. Sickafus, J.M. Wills, N.W. Grimes, J. Am. Ceram. Soc. 82 (12) (1999) 3279–3292.

[29] K.P. Surendran, N. Santha, P. Mohanan, M.T. Sebastian, Eur. Phys. J. B 41 (2004) 301–306.

[30] K.P. Surendran, P.V. Bijumon, P. Mohanan, M.T. Sebastian, Appl. Phys. A 81 (2005) 823–826.

[31] J. Krupka, K. Derzakowski, B. Riddle, J.B. Jarvis, Meas. Sci. Technol. 9 (1998) 1751–1756.

[32] B.W. Hakki, P.D. Coleman, IRE Trans. Microwave Theory Tech. MTT-8 (1960) 402–410.

[33] J.-Y. Ha, J.-W. Choi, H.-J. Kim, S.-J. Yoon, K.H. Yoon, Mater. Chem. Phys. 79 (2003) 261–265.


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