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Pr-doped (1-x)( Na0.5Bi0.5)TiO3-xCaTiO3 ceramics


Journal of Alloys and Compounds 551 (2013) 219–223

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Journal of Alloys and Compounds
journal homepage: www.elsevier.com/locate/jalcom

Photoluminescence and electrical performance of smart material: Pr-doped (1 ? x)(Na0.5Bi0.5)TiO3–xCaTiO3 ceramics
Peng Du, Laihui Luo ?, Weiping Li, Yuepin Zhang, Hongbing Chen
Department of Physics, Ningbo University, 315211 Ningbo, China

a r t i c l e

i n f o

a b s t r a c t
The in?uence of CaTiO3 content on the piezoelectric and photoluminescence performance of the 0.3 mol% Pr-doped NBT–xCT (x = 0, 0.02, 0.04, 0.06, 0.08) ceramics was investigated. The results show that the NBT–xCT:Pr ceramic with x = 0.04 achieves the optimized photoluminescence and piezoelectric properties. A bright red emission at 610 nm and enhanced piezoelectric response are achieved in the ceramics at room temperature. Furthermore, the results show that the photoluminescence performance of the ceramics can be enhanced greatly by poling. The present study opens a way to enhance the photoluminescence of rare-earth doped ferroelectrics. ? 2012 Elsevier B.V. All rights reserved.

Article history: Received 27 June 2012 Received in revised form 1 October 2012 Accepted 3 October 2012 Available online 13 October 2012 Keywords: Lead-free ceramic Piezoelectric Ferroelectric Photoluminescence

1. Introduction Recently, there are a high demand and expectation for intelligent materials in modern industry [1,2], since they can realize sensing and actuating in the same materials [3]. Ferroelectrics are multifunction materials, and they have excellent piezoelectric and pyroelectric properties. In the last few years, it has been reported that multi-?eld coupling, such as electro-mechano, mechano-optic and electro-optic coupling, can be realized in the Pr doped BaTiO3-based ceramic [4]. The unique spontaneous polarization in ferroelectric materials provides us an opportunity to couple different ?elds in a single compound. Approaches through the use of ferroelectric properties have recently been demonstrated successfully in controlling the ferromagnetism, spin polarization, and photovoltaic effects [5–8]. Comparatively, controlling of luminescence in ferroelectrics by polarization has been investigated a little. Fortunately, it was observed that an enhanced emission can be realized by an application of electric ?eld to the Er-doped BaTiO3 [9]. However, ferroelectric BaTiO3 has a low Curie temperature (120 °C) [10], which limits its application greatly. With the growing demand for global environmental protection, lead-free materials draw considerable attention. Sodium bismuth titanate, Na0.5Bi0.5TiO3 (NBT) is one of the most important lead-free piezoelectric materials with a perovskite structure discovered by Smolenskii et al. [11]. It shows strong ferroelectric properties at room temperature, a large remnant polarization (Pr = 38 lC/cm2) and a high coercive ?eld (Ec = 73 kV/cm). NBT is considered to be an alter? Corresponding author. Tel.: +86 574 87600953; fax: +86 574 87600744.
E-mail address: llhsic@126.com (L. Luo). 0925-8388/$ - see front matter ? 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jallcom.2012.10.003

native to Pb(Zr,Ti)O3 ceramic for its large remnant polarization and high Curie temperature TC (TC = 320 °C) [12]. However, the piezoelectric properties of the pure NBT ceramics are unsatisfactory [12]. In order to improve its piezoelectric properties, lots of other materials are added into NBT to form new NBT-based solid solutions, such as NBT– BaTiO3 [12], (1 ? x)Bi0.47Na0.47Ba0.06TiO3–xBa0.77Ca0.23TiO3 [13], (1 ? x)Bi0.5Na0.5TiO3–x(Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 [14]. CaTiO3 (CT) modi?ed NBT ceramics have a lower coercive electric ?eld (Ec) and a higher piezoelectric performance than pure NBT ceramics [15]. Sun et al. observed that Pr-doped ferroelectric Na0.5Bi0.5TiO3 exhibits a strong photoluminescence performance [16]. Furthermore, it’s found that Pr-doped CT with orthorhombic perovskite structure shows an intense red luminescence [17,18]. However, there is not any literature investigating the piezoelectric and photoluminescence performance on the rare-earth doped smart Na0.5Bi0.5TiO3–CaTiO3 ceramics, letting alone investigating the effects of polarization on the photoluminescence. In this work, we present the in?uence of CT content on the piezoelectric and photoluminescence performance of the 0.3 mol% Prdoped (1 ? x)(Bi0.5Na0.5)TiO3–xCaTiO3 (NBT–xCT:Pr, x = 0, 0.02, 0.04, 0.06, 0.08) ceramics, and the poling effect on the photoluminescence properties of the prepared ceramics.
2. Experimental High-purity powders TiO2, Bi2O3, Na2CO3, Pr2O3, and CaCO3 were used as starting materials to synthesize the 0.3 mol% Pr-doped NBT–xCT ceramics by a conventional solid-state reaction technique. The powders in the stoichiometric ratio were mixed in alcohol by agate balls for 10 h, and then dried and calcined at 850 °C for 2 h. They were remilled, mixed thoroughly with a PVA binder solution and pressed into pellets; the pellets were ?nally sintered at 1150 °C for 2 h in air. For carrying

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P. Du et al. / Journal of Alloys and Compounds 551 (2013) 219–223

out the electrical measurement, all the sintered pellets were ground to $1 mm in thickness and silver electrode was coated on both sides. The samples were subjected to a 40 kV/cm electric ?eld at 80 °C in silicone oil bath for 20 min, and then cooled to room temperature under the poling ?eld. The crystal structure of the ceramics was checked using X-ray diffraction (XRD) analyzer (Bruker D8 Advance) with Cu Ka radiation. The piezoelectric coef?cient d33 of the samples was measured by a quasistatic piezoelectric meter (ZJ-3AN, China). Dielectric constant e33 and dielectric loss tan d of the sintered samples as a function of temperature were measured at 100 kHz using a computer-controlled impedance analyzer Agilent 4294A. The polarization vs. electric ?eld (P–E) hysteresis loops were measured at 1 Hz by the RT Premier II ferroelectric workstation. After electrical measurement, the electrodes of the poled ceramics were polished away for the photoluminescence (PL) measurement. Special care was taken to keep the surface of the unpoled and poled samples nearly the same. The photoluminescence (PL) and photoluminescence excitation (PLE) spectra at room temperature were recorded using a spectro?uorometer (Hitachi F-4500).

3. Results and discussion The XRD patterns of the unpoled NBT–xCT:Pr ceramics with 0 6 x 6 0.08 are shown in Fig. 1. The results suggest that all the ceramics possess a pure perovskite phase and no any secondary impurity phase can be observed, indicating that Ca2+ and Pr3+ have diffused into NBT lattices to form a new solid solution NBT–xCT:Pr. From Fig. 1(b), we notice that all the XRD peaks shift slightly to the larger-angle sides with x increasing from 0 to 0.06. It is attributed to the lattice shrink. The smaller size Ca2+ ion (1.34 ?) occupies the A site in the ceramics by substitution of Na+ (1.39 ?) and Bi3+ (1.30 ?). However, as the content of CT exceeds 0.06, the XRD peaks shift slightly to the larger-angle sides; it is due to the occurring of substitution of Ti4+ by Ca2+ in NBT-Pr ceramic. It has been reported that NBT is rhombohedral phase at room temperature [19]. CT is orthorhombic phase at ambient temperature. The XRD patterns of samples in the 2h ranging from 43° to 50° are zoomed in Fig. 1(b). We can see that the peak (202) doesn’t split, indicating that no phase transition from rhombohedral to orthorhombic phase occurs for the ceramics with the increment of Ca content. Fig. 1(c) shows the zoomed XRD patterns of the poled and unpoled samples, and the results show that the peak of poled NBT:Pr shifts a higher angle. The results of unit cell parameters of the poled and unpoled NBT–xCT:Pr ceramics with 0 6 x 6 0.08 were calculated by software Jade 5.0, and the results are shown in Table 1. When x 6 0.04, both lattice parameter c and unit cell volume increase. However, the lattice parameter c and unit cell volume decrease with x increasing further when x > 0.04. Compared with the unpoled samples, the lattice parameter c and unit cell volume of the poled ceramic are larger when x 6 0.06, which means that the lattice distortion of the NBT–xCT:Pr ceramics are induced by the poling ?eld. The lattice distortion will results in decreased lattice

symmetry. However, when CT content x reaches 0.08, the poling ?eld in?uences the unit cell parameters little. Fig. 2(a and b) shows the dielectric constant and loss of the ceramics as a function of temperature. The ceramics with different CT content exhibit two dielectric anomalies at Td and Tm, which are marked in the Fig. 2(a and b), respectively. The ?rst one occurs at the depolarization temperature Td, above which no piezoelectric response is observed in the NBT-based ceramics [12]. This indicates that the long-rang ferroelectric order disappears above Td, and the NBT-based ceramics transform from polar state to nonpolar state. Td can be determined by the ?rst tan d peak [20]. Near Td, lots of interesting results are observed in NBT-based ceramics, such as a large electric-?eld induced strain, constricted P-E loops [21,22]. Fig. 2(b) shows the variation of Td with CT content x. As the CT content increases from 0 to 0.06, it can be seen that Td decreases from 148 °C to 34 °C. When x increases to 0.08, Td is not observed in the curve, meaning that Td is lower than the ambient temperature. NBT is ferroelectric phase at room temperature, and its polar–nonpolar phase transition occurs at $190 °C [23]. CT is not ferroelectric phase. The increment of CT content weakens the ferroelectric properties of the NBT–xCT:Pr ceramics. Therefore, polar–nonpolar phase transition temperature of NBT–xCT:Pr ceramics decreases with the increment of CT content. Consequently, the polar–nonpolar phase transition temperature for NBT– 0.08CT:Pr is lower than the measured temperature range, and the Td peak is not observed in the curve. The second dielectric anomaly appears at temperature Tm, at which maximal dielectric constant is achieved. P–E hysteresis loops of the NBT–xCT:Pr ceramics at room temperature were characterized, as shown in Fig. 3(a). When x 6 0.04, the P–E loop varies little with x. While, as x increases to 0.06, the saturated polarization and coercive electric ?eld of the ceramics decrease greatly. Furthermore, the P–E loop becomes more ?attened and slanted at x = 0.08, showing a very weak characteristic of ferroelectrics. The weak ferroelectric properties of NBT–0.08CT:Pr is attributed to the occurring of depolarization at below room temperature, which is well consistent with Fig. 2. Fig. 3(b) illustrates the variations of the piezoelectric coef?cient d33 with x. It can be seen that the d33 increases with x, and achieves its maximum when x = 0.04. The enhanced piezoelectric response might be attributed to the more complex phase structure and lower coercive electric ?eld due to the substitution of Ca in the ceramics. The value of d33 jumps to a low value as x increases to 0.08. It should be noted that there is still a low d33 for the NBT–0.08CT:Pr ceramic, although polar–nonpolar phase transition occurs at below room temperature. NBT–xCT:Pr ceramics are disordered in A site, which results in the diffusion phase transitions for polar–nonpolar and Curie phase transitions. Therefore, the depolarization occurs in a temper-

(a)
(110)

(b)
(202)
x=0.08 x=0.06 x=0.04 x=0.02 x=0

(c)
Intensity(a.u)

(202)

unpoled poled

x=0.08 x=0.06 x=0.04 x=0.02 x=0

Intensity(a.u)

(101)
x=0.08 x=0.06 x=0.04 x=0.02 x=0

(202) (122) (021) (211) (024)(312)

10

20

30

40

50

60

70

80

44

46

2θ(o)

2θ ( )

48 o

50

44

46

2θ(o)

48

50

Fig. 1. (a) The XRD patterns of the unpoled Pr-doped NBT–xCT:Pr ceramics; (b) the zoomed XRD patterns of unpoled samples; (c) the zoomed XRD patterns of the poled and unpoled samples.

P. Du et al. / Journal of Alloys and Compounds 551 (2013) 219–223 Table 1 Lattice parameters of poled and unpoled NBT–xCT:Pr ceramics with space group R3c. Compositions x Before poling Lattice parameter c (?) The angle of the crystal axes (°) Unit cell volume (?3) Lattice parameter c (?) The angle of the crystal axes (°) Unit cell volume (?3) 0 5.486 89.43 165.09 5.496 89.13 165.95 0.02 5.538 89.68 169.83 5.541 89.42 170.11 0.04 5.548 89.91 170.77 5.553 89.65 171.22 0.06 5.543 89.63 170.30 5.545 89.54 170.48 0.08

221

5.529 89.29 169.01 5.528 89.28 168.91

After poling

(a)
3000
x=0% (Ca) x=2% (Ca) x=4% (Ca) x=6% (Ca) x=8% (Ca)

(b)
Tm Tm Tm Tm
1.0 0.8 0.15 0.6 0.4 0.20
x=0% (Ca) x=2% (Ca) x=4% (Ca) x=6% (Ca) x=8% (Ca)

Td

Td

Td

2000
33

1000

TdTd Td

Tm Td

tanδ tanδ

0.10

Td

0.2 0.0

0.05

0 0 100 200 300
O

0.00 0 50 100
O

40

15

200

Temperature( C)

Temperature ( C)

Fig. 2. (a) The temperature dependence of the dielectric constant and loss for NBT–xCT:Pr ceramics; (b) the zoomed dielectric loss in Fig. 2. (a).

(a)

60 40

(b)
0% (Ca) 2% (Ca) 4% (Ca) 6% (Ca) 8% (Ca)

100 80

P (μC/cm2)

20 0 -20 -40 -60 -60

d33 (pC/N)

60 40 20 0

-40

-20

0

20

40

60

0.00

0.02

0.04

0.06

0.08

E (kV/cm)

Content of CT x

Fig. 3. (a) The polarization vs. electric ?eld hysterests loops of the NBT–xCT:Pr ceramics at room temperature; (b) d33 of the NBT–xCT:Pr ceramics.

ature range, not at a temperature point. Although most of NBT– 0.08CT:Pr is completely nonpolar phase at Td or even >Td, there is still a little polar phase in NBT–0.08CT:Pr ceramic, which results in a low piezoelectric properties in NBT–0.08CT:Pr ceramic. The PL properties of the NBT–xCT:Pr ceramics were examined. There are no shifts about the excitation and emission peaks for all the NBT–xCT:Pr ceramics. The PL spectra of the poled and unpoled NBT–xCT:Pr samples are shown in Fig. 4. From the excitation spectra monitored at 610 nm, we can see three strong sharp excitation peaks between 440 and 500 nm. The broad excitation band is attributed to the Pr3+ (4f) ? Ti4+ (3d) charge transition [24]. The excitation peaks between 440 and 500 nm are due to the typical 4f–4f transition from the 3H4 ground state to the excited states 3 PJ (J = 0, 1, 2) of Pr3+ [16,18]. The intensely sharp peaks around 453, 478, and 494 nm are related to the 3H4 ? 3P2, 3H4 ? 3P1, and 3H4 ? 3P0 transitions. The excitation spectrum of NBT–xCT:Pr

ceramics excitation band covers the emission wavelength of all commercial blue light-emitting diodes chips (450–470 nm) [16]. This indicates that NBT–xCT:Pr ceramics have a good commercial use potential as photoluminescence materials or other integrated optoelectronic devices. The PL spectrum shows a strong red emission band near 610 nm upon 478 nm light excitation. The strong red emission band at 610 nm is due to the inter-4f transition from the excited 1D2 to the ground state 3H4 [16,17], and the weak red emission located at 655 nm is due to the 3P0 ? 3F2 transition [25,26]. The intensity of red emission at 610 nm of the NBT–xCT:Pr ceramics as a function of CT content x under a light 478 nm excitation has been shown in the Fig. 4(a). The results show that the intensity of that NBT–xCT:Pr ceramics increase with the CT content and reach their maximum at x = 0.04. The symmetry of orthorhombic CT is lower than that of rhombohedral NBT, and the Ca substitution in NBT ceramics will result in decreased lattice symmetry

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P. Du et al. / Journal of Alloys and Compounds 551 (2013) 219–223

(a)50
40

Intensity (a.u)

Intensity (a.u)

0% (Ca) 2% (Ca) 4% (Ca) 6% (Ca) 8% (Ca)

(b) 50
3H 4 1D 2
40 30 20 10 0 550

3H 4 1D 2

unpoled poled

30 20 10 0

3P 3 1 P0 3H 3 4 H4 3H 4 3P 2

3F 2 3P 0

3F 2 3P 0
600 650 700 0.00

3H 4 1D 2
0.03 0.06 0.09

450

500

600

700

Wavelength (nm)

Wavelength (nm)

Content of CT x

Fig. 4. (a) PLE and PL spectra of the NBT–xCT:Pr (kex = 478 nm, kem = 610 nm) ceramics. (b) The PL spectra of the poled and unpoled NBT–0.04CT:Pr samples and the dependence of emission intensity on content of CT.

for the NBT-based ceramics. Therefore, the enhanced red luminescence can be attributed to that the decreased symmetry of the NBT–Pr ceramics after Ca substitution [27]. However, when the CT content further increases to 0.06, the lattice symmetry of the ceramic increases due to the decrement of Td [28]. The behavior of PL performance as a function of CT content in the ceramics is the same as that of the piezoelectric performance in Fig. 3(b). Compared with that of the unpoled samples, the intensity of red emission of the poled ones with strong ferroelectric properties at 610 nm is higher, as is shown in Fig. 4(b). However, when excessive Ca substitution, the red emission of NBT–0.08CT:Pr ceramic with weak ferroelectric performance does not show an obvious change, indicating that poling has no effect on the nonpolar NBT–0.08CT:Pr ceramic. The results show that the PL properties of the ferroelectric ceramics are dependent on the electric poling. The enhanced PL performance by poling for the ferroelectric NBT–xCT:Pr ceramics is ascribed to the decreased crystal symmetry of the host material. The ferroelectric perovskite NBT–xCT:Pr ceramics used in this study is non-centrosymmetric at room temperature, and Ti is shifted to the negatively charged oxygen atoms, producing a spontaneous polarization. Therefore, the perturbation caused by the odd-order term of crystal-?eld forces the forbidden 4f–4f electric dipole transitions allowed, leading to the observed PL emission at room temperature without poling [9], as shown in Fig. 4. After being poled, the lattice distortion is induced by the poling ?eld, which promotes the structure asymmetry of the NBT–xCT:Pr host, as is proved in Table 1. The change of the lattice symmetry will give rise to remarkable effect on the local ?eld around the Pr3+ [29]. It is well known that the 4f levels are well shielded by outer 5s- and 5pelectron shells and show a negligible interaction with the host. The presence of a crystal ?eld in most crystalline hosts would shift 5d energy level of Pr3+ and allows stronger 4f ? 4f emission occurring [29]. On the other hand, the probability for spontaneous emission of electric dipole transition can be enhanced by the increased asymmetry of the lanthanide ion sites [30]. Herein, the PL intensity is enhanced by poling. Besides, the domain size also affects the PL performance of the ceramics. After poling, the domain size of the NBT–xCT:Pr ceramics increase, which will reduce the optical loss during light propagation. The results of Fig. 4 show that poling is an effective approaching to enhance the photoluminescence of the rare-earth doped ferroelectrics.

moderate Ca substitution, both the piezoelectric response and PL performance increase, without an obvious decrement of ferroelectric properties. Upon the excitation of 478 nm light, the sample exhibits a strong emission peak centered at 610 nm. The NBT– xCT:Pr ceramic with x = 0.04 shows the optimum photoluminescence and piezoelectric properties. The excitation bands are mainly located at 440–500 nm. In addition, the red emission of the ferroelectric ceramics after poling is enhanced greatly, indicating that poling is an effective approaching to enhance the photoluminescence of the rare-earth doped ferroelectrics. The results indicate that the NBT–0.04CT:Pr ceramic is an excellent multifunctional smart material. Acknowledgments This work was supported by the National Natural Science Foundation of China(51002082, 11004113), The Prior Project in Key Science & Technology Program of Zhejiang Province of China (Grant No. 2009C11144), Natural Science Foundation of Ningbo (2012A610118), the Outstanding (Post-graduate) Dissertation Growth Foundation of Ningbo University (PY20110011) and the K.C. Wong Magna Foundation in Ningbo University (xkzl1203). References
[1] N. Muto, H. Yanagida, T. Nakatsuji, M. Sugita, Y. Ohtsuka, Y. Arai, Smart Mater. Struct. 1 (1992) 324. [2] I. Tokarev, M. Motornov, S. Minko, J. Mater. Chem. 19 (2009) 6932. [3] K. Uchino, Piezoelectric Actuators and Ultrasonic Motors, Kluwer Academic, Boston, 1997. [4] X. Wang, C. Xu, H. Yamada, K. Nishikubo, X. Zheng, Adv. Mater. 17 (2005) 1254. [5] J.H. Lee, L. Fang, E. Vlahos, X. Ke, Y.W. Jung, L.F. Kourkoutis, J. Kim, P.J. Ryan, Nature 476 (2011) 114. [6] T. Choi, S. Lee, Y.J. Choi, V. Kiryukhin, S.W. Cheong, Science 324 (2009) 63. [7] V. Garcia, M. Bibes, L. Bocher, S. Valencia, F. Kronast, A. Crassous, X. Moya, Science 327 (2010) 106. [8] S.M. Wu, S.A. Cybart, P. Yu, M.D. Rossell, J.X. Zhang, R. Ramesh, R.C. Dynes, Nat. Mater. 9 (2010) 756. [9] J. Hao, Y. Zhang, X. Wei, Angew. Chem. 123 (24) (2011) 7008. [10] W.J. Merz, Phys. Rev. 78 (1) (1950) 52. [11] G.A. Smolenskii, V.A. Isupov, A.I. Agranovskaya, N.N. Krainik, Sov. Phys. Solid State 2 (1961) 2651. [12] T. Takenaka, K. Maruyama, K. Sakata, Jpn. J. Appl. Phys. 30 (10) (1991). [13] L. Luo, F. Ni, H. Zhang, H. Chen, J. Alloys Comp. 536 (2012) 113. [14] Q. Gou, J. Wu, A. Li, B. Wu, D. Xiao, J. Zhou, J. Alloys Comp. 521 (2012) 4. [15] T. Takenaka, K. Sakata, K. Toda, Jpn. J. Appl. Phys. 28 (1989) 59. [16] H. Sun, D. Peng, X. Wang, M. Tang, Q. Zhang, X. Yao, J. Appl. Phys. 110 (2011) 016102. [17] R. Chen, D. Chen, J. Alloys Comp. 476 (2009) 671. [18] P.T. Diallo, K. Jeanlouis, P. Boutinaud, R. Mahiou, J.C. Cousseins, J. Alloys Comp. 323 (12) (2001) 218. [19] T. Zhou, R. Huang, X. Shang, Appl. Phys. Lett. 90 (2007) 182903. [20] K. Yoshii, Y. Hiruma, H. Nagata, T. Takenaka, Jpn. J. Appl. Phys. 45 (5B) (2006) 4493.

4. Conclusions In summary, the photoluminescence and electrical properties of the Ca-substituted NBT:Pr ceramics have been investigated. With

P. Du et al. / Journal of Alloys and Compounds 551 (2013) 219–223 [21] S. Zhang, A.B. Kounga, E. Aulbach, H. Ehrenberg, J. Rodel, Appl. Phys. Lett. 91 (2007) 112906. [22] Y. Guo, M. Gu, H. Luo, Y. Liu, R.L. Withers, Phys. Rev. B 83 (5) (2011) 054118. [23] Y. Hiruma, H. Nagata, T. Takenaka, J. Appl. Phys. 105 (2009) 084112. [24] P. Boutinaud, E. Cavalli, R. Velchuri, M. Vithal, J. Phys.: Condens. Matter 24 (2012) 075502. [25] D. Peng, H. Sun, X. Wang, J. Zhang, M. Tang, X. Yao, J. Alloys Comp. 511 (2012) 159.

223

[26] Q.J. Chen, W.J. Zhang, X.Y. Huang, G.P. Dong, M.Y. Peng, Q.Y. Zhang, J. Alloys Comp. 513 (2012) 139. [27] X.Y. Wang, Y.X. Tang, X.Y. He, X. Zeng, Q.Z. He, Z.F. Peng, D.Z. Sun, Ferroelectrics 411 (2009) 52. [28] Y. Hiruma, H. Nagata, T. Takenaka, J. Appl. Phys. 104 (2008) 124106. [29] S.Y. Kang, Y.H. Kim, J. Moon, K.S. Kang, Jpn. J. Appl. Phys. 48 (2009) 052301. [30] M.J. Weber, Phys. Rev. 157 (2) (1967) 262.


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