Transport critical current density of ([Bi.sub.1.6][Pb.sub.0.4])[Sr.sub.2][Ca.sub.2][Cu.sub.3][O.sub.10] ceramic superconductor with different nanosized [Co.sub.3][O.sub.4] addition.
The critical current density, [J.sub.c], is one of the most significant parameters for the successful application of high-[T.sub.c] superconductors. The pinning potential is one of the important factors that determine the critical current density. [J.sub.c] can be improved by introducing
efficient pinning center with size that matches the coherence length, which can improve pinning potential and suppress the flux flow [1, 2].
Extensive researches have been done to improve the flux pinning properties of the [Bi.sub.1.6][Pb.sub.0.4][Sr.sub.2][Ca.sub.2][Cu.sub.3][O.sub.10] (Bi-2223) system [2-19]. Elemental substitution and addition of nanosized particles in high-[T.sub.c] superconductors are an easy and efficient method to improve the transport properties. Much effort has been done to improve intergrain links and the properties of the Bi-based superconductor, such as adding Al, Cr, Mg, Cd, Ag, Ni, Nb, Li, La, and Nd into high-[T.sub.c] superconductors [2-11].
The critical current density and transition temperature of Sm added samples were found to be higher than those of the pure samples with a maximum [J.sub.c] given by x = 0.02 wt.%, which is seven times higher than nonadded sample . In [Cr.sub.2][O.sub.3] added Bi-2223 samples, the maximum Tc and [J.sub.c] were observed for the sample with 0.5 wt.% . In MgO added Bi[Sr.sub.2]Ca[Cu.sub.2]O[[delta] (Bi-2212) samples, the transition is narrow and the volume fraction increases with addition up to 9 wt.% . The volume fraction of the Bi-2223 phase, lattice parameter, and zero-resistance temperature, [T.sub.c-zero], decrease with increasing MgC[O.sub.3] content . The [Fe.sub.3][O.sub.4] magneticnanoparticle and SiC have the ability to enhance the critical current density in Bi-2[Sr.sub.2][Ca.sub.2][Cu.sub.3][O.sub.10]/Ag tape [14,18].
Flux pinning can be optimized if the particle size is carefully controlled. With judicious addition level, these particles can improve flux pinning . The pinning strengths of the flux lines can be enhanced by direct magnetic interaction of vortices with magnetic pinning centers.
The two important characteristic lengths in superconductors are the coherence length [xi] and penetration depth [lambda]. The critical current density is expected to increase if the pinning center is larger than [xi] but smaller than [lambda] . For [Br.sub.2][Sr.sub.2][Ca.sub.2][Cu.sub.3][O.sub.10] system, [xi] = 2.9nm and [lambda] = 60-1000 nm. Formagnetic nanoparticles, a strong interaction between flux line network and the system can be expected if [xi] < L < [lambda], where L is the particle size . The range between [xi] and [lambda] is large and it is interesting to investigate the effect of different magnetic nanosized particles, that is, between 2.9nm and 60 nm on (Bi,Pb-2223) superconductor.
Most studies on the nanosized particle addition into (Bi,Pb)-2223 have only been carried outwith one average size. Preliminary results on the effect of Co3O4 on the formation of the Bi-2223 phase have been reported . In this paper the effects of magnetic [Co.sub.3][O.sub.4] addition with average sizes 10, 30, and 50 nm in [Bi.sub.1.6][Pb.sub.0.4][Sr.sub.2][Ca.sub.2][Cu.sub.3][O.sub.10][([Co.sub.3][O.sub.4]).sub.x] with x = 0-0.05 were studied. These sizes are larger than E but smaller than A which satisfies the condition in . This objective of this research was to determine the effect of different nanosized [Co.sub.3][O.sub.4] on the phase formation, structure, microstructure, and transport critical current properties of Bi-2223 superconductor.
2. Experimental Details
Superconducting powders precursor with nominal composition [Bi.sub.1.6][Pb.sub.0.4][Sr.sub.2][Ca.sub.2][Cu.sub.3][O.sub.10] were synthesized by using the coprecipitation method. The material was prepared using metal acetates of bismuth, lead, strontium, calcium and copper (purity [greater than or equal to] 99.99%), oxalic acid, deionized water, and isopropanol. The dried-up powders were ground manually in agate mortar and calcined at 730[degrees]C for 12 h followed by an intermediate grinding before the second calcination at 845[degrees] C for 24 h. After cooling, the calcined powders were ground again and after that nanosized [Co.sub.3][O.sub.4] (US Research Nanomaterials Inc.) with average particle size of 10, 30, and 50 nm were added to the precursor powders with nominal composition [Bi.sub.1.6][Pb.sub.0.4][Sr.sub.2][Ca.sub.2][Cu.sub.3][O.sub.10][([Co.sub.3][O.sub.4]).sub.x] with x = 0.00, 0.01, 0.02, 0.03, 0.04, and 0.05 wt.%. The samples were thoroughly mixed, ground, pressed into pellet of 2 mm thickness and 12.5 mm diameter, and sintered at 850[degrees]C for 48 h.
The electrical resistance-temperature measurements were carried out by the four-point probe technique in conjunction with a CTI cryogenics closed-cycle refrigerator (Model 22). The four-point probe method using the 1 [micro]V/cm criterion was used to measure the transport critical current density between 30 K and 77 K.
The XRD diffraction patterns were recorded using a Bruker D8 Advance diffractometer with CuK[alpha] radiation. The microstructure of the samples was observed using a scanning electron microscope (SEM) Philips XL 30. The distribution of nano-[Co.sub.3][O.sub.4] in the sample and the presence of the different phases were analyzed by using a Philips energy dispersive X-ray analyzer (EDX) model PV99. The size of [Co.sub.3][O.sub.4] was determined using a Philips transmission electron microscope (TEM) model CM12.
3. Results and Discussion
TEM micrograph of the [Co.sub.3][O.sub.4] nanoparticles with average size around 30 nm is shown in Figure 1. Figures 2, 3, and 4 show the XRD patterns of the sample added with 10, 30, and 50 nm [Co.sub.3][O.sub.4], respectively. The samples consist of a mixture of Bi-2223 and Bi-2212 phase. H and L indicate the high-[T.sub.c] Bi-2223 phase and low-[T.sub.c] Bi-2212 phase, respectively. The volume fraction of the phases for all the samples is given in Table 1. Samples with x = 0.01 wt.% (10 nm), x = 0.02 wt.% (30 nm), and x = 0.01 wt.% (50 nm) showed the highest percentage ofBi-2223 phase, that is, 72,74, and 72%, respectively. Further increase of [Co.sub.3][O.sub.4] decreased the percentage of the Bi-2223 phase and increased the percentage of the Bi-2212. The intensity of the peaks corresponding to the Bi-2223 phase decreases and the intensities of peaks corresponding to the Bi-2212 phase increase with further increase in [Co.sub.3][O.sub.4]. The lattice parameters for the x = 0 samples were a = b = 5.413 [+ or -] 0.006 A and c = 37.097 [+ or -] 0.006 A. A slight increase in the c lattice parameter with almost no change in the a and b parameters was observed in the nano-[Co.sub.3][O.sub.4] added samples. The [Co.sub.3][O.sub.4] reflections were not observed in the XRD patterns due to the fact that the x values are too small to be detected. Addition of 10 and 30 nm [Co.sub.3][O.sub.4] from x = 0.01 to 0.04 wt.% increased the Bi-2223 phase volume fraction.
Figure 5 shows the electrical resistance as a function of temperature between 60 and 200 K for all the samples. The dc electrical resistance measurements show metallic behavior in the normal state and a well-defined superconducting transitions for all samples. All the samples show the zero electrical resistance [T.sub.c-zero] within the range of 91 to 102 K (Table 1), while onset temperature [T.sub.c-onset] is between 83 and 115 K. The nonadded sample showed [T.sub.c-zero] at 100 K. Samples with x = 0.01 wt.% [Co.sub.3][O.sub.4] (10 nm) showed the highest [T.sub.c-zero] at 102 K. The high Tc for the x = 0.01 wt.% sample may be due to homogeneity in the sample. Excessive [Co.sub.3][O.sub.4] degraded the superconductivity of Bi-2223, which can affect the transport properties in this type of material. The lower [T.sub.c-zero] with increasing [Co.sub.3][O.sub.4] content also could be interpreted as a result of the suppression of superconductivity by [Co.sub.3][O.sub.4] .
Figure 6 shows the [J.sub.c] values at various temperatures for the 10, 30, and 50 nm [Co.sub.3][O.sub.4] added samples. The magnitude of [J.sub.c] in these samples is similar to those reported in the Y-based  and Bi-based 24] polycrystalline superconductors. It is clear that the addition of a small amount of [Co.sub.3][O.sub.4] enhanced the current-carrying capacity of the Bi-2223 ceramics. For the undoped sample, the [J.sub.c] at 77 K is about 26mA/[cm.sup.2]. The highest value of [J.sub.c] was observed in the x = 0.03 wt.% [Co.sub.3][O.sub.4] (10nm) sample and x = 0.02 wt.%
[Co.sub.3][O.sub.4] (30 nm) sample. At 77 K, [J.sub.c] of the 10 nm and 30 nm [Co.sub.3][O.sub.4] added samples was 6 and 13 times larger than the nonadded samples, respectively. However, the addition of [Co.sub.3][O.sub.4] (50 nm) decreased the [J.sub.c] at 77 K (0.01-0.05 wt.%) compared to the nonadded sample. The [J.sub.c] of the sample increased to 358 (mA/[cm.sup.2]) in the 0.03 wt.% [Co.sub.3][O.sub.4] (30 nm) sample at 77 K. The [J.sub.c] results, showed that nano-[Co.sub.3][O.sub.4] (30 nm) with x = 0.02 wt.% is the optimum amount for the highest [J.sub.c]. The added [Co.sub.3][O.sub.4] nanoparticles towards enhancing the critical current density for low concentration and for higher concentration it acts to suppress [J.sub.c]. The enhancing contribution is due to their magnetic and core vortex pinning forces. The suppressing contribution is due to their effect on the grain size and shape .
Figure 7 shows the scanning electron micrograph of x = 0.03 wt.% (10 nm), x = 0.02 wt.% (30 nm), and 0.01 wt.% (50 nm) samples. For the nonadded sample, clean and flaky grains are observed which is the typical structure of the Bi2223 system. The grain morphology of all the added samples is more or less identical except for minor variations in texture and porosity. The undoped sample showed the largest grain size. XRD analysis indicated that all samples with nano[Co.sub.3][O.sub.4] showed the Bi-2212 peaks, which correspond to the low Tc phase. However, the micrograph of x = 0.03 wt.% of [Co.sub.3][O.sub.4] (50 nm) showed a different surface morphology compared to nonadded sample. The microstructures reveal a minor difference in the porosity levels with lower levels of [Co.sub.3][O.sub.4] . Thus, the addition of [Co.sub.3][O.sub.4] enhanced the sample morphology slightly. Thus, the [Co.sub.3][O.sub.4] nanoparticles have a clear effect on the microstructure of the sample. The decrease of the porosity level enhanced the critical current density . The distribution [Co.sub.3][O.sub.4] in the samples with x = 0.03 (10 nm), x = 0.02 (30 nm), and x = 0.01 (50 nm) is shown as white dots. The nanoparticles were dispersed on the surface of the grains and filled the weak links between the grains. For sample with x = 0.01 (50 nm), there are many voids and pores. Moreover, the grain texture of this sample is also reduced compared to other samples.
In conclusion, the effect of nano-[Co.sub.3][O.sub.4] addition on flux pinning capability of bulk superconductor ([Bi.sub.1.6][Pb.sub.0.4])[Sr.sub.2][Ca.sub.2][Cu.sub.3][O.sub.10] was investigated. The larger [Co.sub.3][O.sub.4] nanoparticle (50 nm) had a greater degradation effect on superconductivity of the Bi-based materials. The highest [J.sub.c] was observed in sample with x = 0.02 wt.% [Co.sub.3][O.sub.4] (30 nm). Our results showed that suppression factors of the critical current density may dominate the enhancing factors for higher [Co.sub.3][O.sub.4] concentrations. With judicious amounts of [Co.sub.3][O.sub.4] nanoparticle of size 10 or 30 nm, the critical current density can be improved in the Bi-2223 superconductor.
Conflict of Interests
The authors declare that there is no conflict of interests regarding the publication of this paper.
This research has been supported by the Ministry of Education of Malaysia under Grant no. FRGS/2/2013/SG02/UKM/ 01/1 and Universiti Kebangsaan Malaysia under Grant nos. DLP-2011-018 and DIP-2012-032.
 R. Weinstein, R.-P. Sawh, A. Gandini, B. Mayes, and D. Parks, "Is it really possible to increase Jc by reducing the pinning potential?" Superconductor Science and Technology, vol. 20, no. 9, pp. S167-S173, 2007.
 A. Ghattas, M. Annabi, M. Zouaoui, F. B. Azzouz, and M. B. Salem, "Flux pinning by Al-based nano particles embedded in polycrystalline (Bi,Pb)-2223 superconductors," Physica C, vol. 468, no. 1, pp. 31-38, 2008.
 H. Abbasi, J. Taghipour, and H. Sedghi, "Superconducting and transport properties of (Bi-Pb)-Sr-Ca-Cu-O with [Cr.sub.2][O.sub.3] additions," Journal of Alloys and Compounds, vol. 494, no. 1-2, pp. 305-308, 2010.
 H. Abbasi, J. Taghipour, and H. Sedghi, "The effect of MgC[O.sub.3] addition on the superconducting properties of Bi2223 superconductors," Journal of Alloys and Compounds, vol. 482, no. 1-2, pp. 552-555, 2009.
 S. E. Mousavi Ghahfarokhi and M. Zargar Shoushtari, "Structural and physical properties of Cd-doped [Bi.sub.1.6][Pb.sub.0.4][Sr.sub.2][Ca.sub.2][Cu.sub.3][O.sub.u] superconductor," Physica B, vol. 405, no.'22, pp. 4643-4649, 2010.
 I. H. Gul, F. Amin, A. Z. Abbasi, M. Anis-ur-Rehman, and A. Maqsood, "Effect of [Ag.sub.2]C[O.sub.3] addition on the morphology and physical properties of Bi-based (2223) high-Tc superconductors," Physica C, vol. 449, no. 2, pp. 139-147, 2006.
 B. A. Albiss, I. M. Obaidat, M. Gharaibeh, H. Ghamlouche, and S. M. Obeidat, "Impact of addition of magnetic nanoparticles on vortex pinning and microstructure properties of BiSrCaCuO superconductor," Solid State Communications, vol. 150, no. 3334, pp. 1542-1547, 2010.
 H. Sozeri, N. Ghazanfari, H. Ozkan, and A. Kilic, "Enhancement in the high-Tc phase of BSCCO superconductors by Nb addition," Superconductor Science and Technology, vol. 20, no. 6, pp. 522-528, 2007.
 V. Mihalache, G. Aldica, S. Popa, F. Lifei, and D. Miu, "Effect of [Li.sub.2]C[O.sub.2] addition on the [Bi.sub.1.7][Pb.sub.0.4][Sr.sub.1.5][Ca.sub.2.5][Cu.sub.3.6][O.sub.x] superconducting system," Materials Letters, vol. 58, no. 24, pp. 30403044, 2004.
 A. Biju, K. Vinod, R. P. Aloysius, and U. Syamaprasad, "Improved superconducting properties by La addition in (Bi,Pb)-2212 bulk superconductor," Journal of Alloys and Compounds, vol. 431, no. 1-2, pp. 49-55, 2007
 R. P. Aloysius, P. Guruswamy, and U. Syamaprasad, "Enhanced critical current density in (Bi,Pb)-2223 superconductor by Nd addition in low percentages," Physica C, vol. 426-431, pp. 556-562, 2005.
 V. G. Prabitha, A. Biju, R. G. A. Kumar, P. M. Sarun, R. P. Aloysius, and U. Syamaprasad, "Effect of Sm addition on (Bi,Pb)-2212 superconductor," Physica C, vol. 433, no. 1-2, pp. 28-36, 2005.
 K. Christova, A. Manov, J. Nyhus et al., "[Bi.sub.2][Sr.sub.2]Ca[Cu.sub.2][O.sub.x] bulk superconductor with MgO particles embedded," Journal of Alloys and Compounds, vol. 340, no. 1-2, pp. 1-5, 2002.
 R. Abd-Shukor and W. Kong, "Magnetic field dependent critical current density of Bi-Sr-Ca-Cu-O superconductor in bulk and tape form with addition of [Fe.sub.3][O.sub.4] magnetic nanoparticles," Journal of Applied Physics, vol. 105, no. 7, Article ID 07E311, 2009.
 V Shelke, H. S. Tewari, N. K. Gaur, and R. K. Singh, "Effect of Hg addition on synthesis of Bi-based superconductors," Physica C, vol. 300, no. 3-4, pp. 217-224, 1998.
 M. Diantoro, W. Loeksmanto, M. O. Tjia et al., "AC loss and critical current density in Bi-2223 tapes with oxide additives and reinforced Ag sheaths," Physica C, vol. 378-381, no. 2, pp. 1143-1147, 2002.
 K. T. Lau, S. K. Chen, and R. Abd-Shukor, "Comparative study on the transport critical current density of Bi-2223 and Tl-1212 Ag-sheathed superconductor tapes in low magnetic fields," Physica C, vol. 377, no. 4, pp. 547-552, 2002.
 Z. Q. Yang, X. D. Su, G. W Qiao, Y. C. Guo, S. X. Dou, and F. R . De Boer, "Flux-pinning enhancement in Ag-sheathed Bi-2223 tapes by nanometer-SiC addition," Physica C, vol. 325, no. 3-4, pp. 136-142, 1999.
 E. Guilmeau, B. Andrzejewski, and J. G. Noudem, "The effect of MgO addition on the formation and the superconducting properties of the Bi2223 phase," Physica C, vol. 387, no. 3-4, pp. 382-390, 2003.
 U. Al Khawaja, M. Benkraouda, I. M. Obaidat, and S. Alneaimi, "Numerical simulations on the role of the defect size on the critical current in high-temperature superconductors," Physica C, vol. 442, no. 1, pp. 1-8, 2006.
 I. F. Lyuksyutov and D. G. Naugle, "Frozen flux superconductors," Modern Physics Letters B, vol. 13, no. 15, pp. 491-497, 1999.
 A. N. Jannah, R. Abd-Shukor, and H. Abdullah, "Effect of [Co.sub.3][O.sub.4] nanoparticles addition on (Bi, Pb)-2223 superconductor," World Academy of Science, Engineering and Technology, vol. 75, pp. 367-370, 2013.
 K. E. Oldenburg, W. A. Morrison, and G. C. Brown, "Critical current density of Y[Ba.sub.2][Cu.sub.3][O.sub.7-x]," The American Journal of Physics, vol. 61, no. 9, pp. 832-834, 1993.
 M. Anis-ur-Rehman and M. Mubeen, "Synthesis and enhancement of current density in cerium doped Bi(Pb)Sr(Ba)-2223 high Jc superconductor," Synthetic Metals, vol. 162, pp. 1769-1774, 2012.
Nur Jannah Azman, (1) Huda Abdullah, (2) and Roslan Abd-Shukor (1)
(1) School of Applied Physics, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
(2) Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and the Built Environment,
Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
Correspondence should be addressed to Roslan Abd-Shukor; email@example.com
Received 19 December 2013; Accepted 7 January 2014; Published 19 February 2014
Academic Editor: Ram N. P. Choudhary
TABLE 1: Zero-resistance temperature ([T.sub.c-zero]), volume fraction, critical current density([J.sub.c]) at 30 K, and 77 Kin self-field. x (wt.%) Volume fraction [T.sub.c-zero] Bi-2223 (%) Bi-2212 (%) ([+ or -] 1K) (10 nm) 0 51 49 100 0.01 61 39 102 0.02 61 39 101 0.03 72 28 97 0.04 63 37 99 0.05 51 49 95 (30 nm) 0 51 49 100 0.01 71 29 97 0.02 74 26 95 0.03 67 33 91 0.04 53 47 98 0.05 47 53 94 (50 nm) 0 51 49 100 0.01 72 28 97 0.02 44 56 97 0.03 48 52 96 0.04 37 63 95 0.05 37 63 93 x (wt.%) [J.sub.c] at 30 K [J.sub.c] at 77 K (mA/[cm.sup.2]) (mA/[cm.sup.2]) (10 nm) 0 371 26 0.01 412 108 0.02 590 122 0.03 1232 358 0.04 725 342 0.05 986 82 (30 nm) 0 371 26 0.01 411 40 0.02 1742 878 0.03 1145 854 0.04 1025 731 0.05 440 236 (50 nm) 0 371 26 0.01 1389 923 0.02 1018 609 0.03 1262 508 0.04 755 250 0.05 428 170
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||Research Article|
|Author:||Azman, Nur Jannah; Abdullah, Huda; Abd-Shukor, Roslan|
|Publication:||Advances in Condensed Matter Physics|
|Date:||Jan 1, 2014|
|Previous Article:||Electronic structure and optical properties of Ga[As.sub.1-x][Bi.sub.x] alloy.|
|Next Article:||Evolution of helium with temperature in neutron-irradiated [sup.10]B-doped aluminum by small-angle X-ray scattering.|