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Phase evolution of MgB2 prepared under high pressure

Published online by Cambridge University Press:  29 February 2012

Yaxin Sun  and
Dongli Yu
Yaxin Sun
Affiliation:
State Key Laboratory of Metastable Materials Science and Technology and College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, China and School of Materials Science and Engineering, Anhui University of Technology, Ma’anshan 243000, China
Dongli Yu
Affiliation:
State Key Laboratory of Metastable Materials Science and Technology and College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, China
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Abstract

MgB2 superconductors were synthesized at high pressure and high temperature (HPHT) using pure Mg and B as raw materials. The effects of the experimental conditions such as pressure and temperature on phase evolution were studied using X-ray diffraction (XRD), scanning electron microscope (SEM), and DC magnetization techniques. Results showed that high pressure and high temperature are two important factors for synthesizing the MgB2 phase. Stable MgB2 can be most effectively obtained in a pressure-temperature region from 3 to 6 GPa and between the melting points of Mg up to 1100 to 1300 °C. MgB2 starts to decompose into MgB4 at higher temperatures and pressures. The decomposition temperature of MgB2 increases with increasing pressure. The superconducting transition temperature Tc(bulk) was measured to be 38.0 to 38.8 K for MgB2 prepared at 900 to 1000 °C under 3 GPa. The larger grains and better crystalline perfection contribute to the higher Tc(bulk) and the narrower ΔT.

Keywords

MgB2high pressurehigh temperaturephase evolution
Type
Technical Articles
Information
Powder Diffraction , Volume 23 , Issue 4 , December 2008 , pp. 334 - 337
Copyright
Copyright © Cambridge University Press 2008

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References

Brutti, S., Ciccioli, A., Balducci, G., Gigli, G., Manfrinetti, P., and Palenzona, A. (2002). “Vaporization thermodynamics of MgB2 and MgB4,” Appl. Phys. Lett.APPLAB10.1063/1.1471382 80, 2892–2894.CrossRefGoogle Scholar
Canfield, P. C., Finnemore, D. K., Bud’ko, S. L., Ostenson, J. E., Lapertot, G., Cunningham, C. E., and Petrovic, C. (2001). “Superconductivity in dense MgB2 wires,” Phys. Rev. Lett.PRLTAO10.1103/PhysRevLett.86.2423 86, 2423–2426.CrossRefGoogle ScholarPubMed
Errandonea, D., Boehler, R., and Ross, M. (2001). “Melting of the alkaline-earth metals to 80 GPa,” Phys. Rev. BPRBMDO10.1103/PhysRevB.65.012108 65, 012108.CrossRefGoogle Scholar
Fan, Z. Y., Hinks, D. G., Newman, N., and Rowell, J. M. (2001). “Experimental study of MgB2 decomposition,” Appl. Phys. Lett.APPLAB10.1063/1.1383804 79, 87–89.CrossRefGoogle Scholar
Grasso, G., Malagoli, A., Ferdeghini, C., Roncallo, S., Braccini, V., and Siri, A. S. (2001). “Large transport critical currents in unsintered MgB2 superconducting tapes,” Appl. Phys. Lett.APPLAB10.1063/1.1384905 79, 230–232.CrossRefGoogle Scholar
Liu, Z.-K., Schlom, D. G., Li, Q., and Xi, X. X. (2001). “Thermodynamics of the Mg-B system: Implications for the deposition of MgB2 thin films,” Appl. Phys. Lett.APPLAB10.1063/1.1376145 78, 3678–3680.CrossRefGoogle Scholar
Nagamatsu, J., Nakagawa, N., Muranaka, T., Zenitani, Y., and Akimitsu, J. (2001). “Superconductivity at 39 K in magnesium diboride,” Nature (London)NATUAS10.1038/35065039 410, 63–64.CrossRefGoogle ScholarPubMed
Prikhna, T. A., Gawalek, W., Surzhenko, A. B., Moshchil, V. E., Sergienko, N. V., Savchuk, Ya. M., Melnikov, V. S., Nagorny, P. A., Habisreuther, T., Dub, S. N., Wendt, M., Litzkendorf, D., Dellith, J., Schmidt, Ch., Krabbes, G., and Vlasenko, A. V. (2002). “High-pressure synthesis of MgB2 with and without tantalum additions,” Physica CPHYCE6 372-376, 1543–1545.CrossRefGoogle Scholar
Shi, Q. Z., Liu, Y. C., Zhao, Q., and Ma, Z. Q. (2008). “Phase formation process of bulk MgB2 analyzed by differential thermal analysis during sintering,” J. Alloys Compd.JALCEU 458, 553–557.CrossRefGoogle Scholar
Toulemonde, P., Musolino, N., and Flükiger, R. (2003). “High-pressure synthesis of pure and doped superconducting MgB2 compounds,” Supercond. Sci. Technol.SUSTEF10.1088/0953-2048/16/2/318 16, 231–236.CrossRefGoogle Scholar
Yamamoto, A., Shimoyama, J., Ueda, S., Katsura, Y., Horii, S., and Kishio, K. (2005). “Improved critical current properties observed in MgB2 bulks synthesized by low-temperature solid-state reaction,” Supercond. Sci. Technol.SUSTEF10.1088/0953-2048/18/1/019 18, 116–121.CrossRefGoogle Scholar
Yan, G., Feng, Y., Lu, Y. F., Zhou, L., Jing, W. X., and Wen, H. H. (2006). “Influences of heat treatment and doping on microstructure and superconducting properties of MgB2 superconductor,” Physica C PHYCE6 445-448, 466–470.CrossRefGoogle Scholar
Yan, S. C., Yan, G., Liu, C. F., Lu, Y. F., and Zhou, L. (2007). “Experimental study on the phase formation for the Mg–B system in Ar atmosphere,” J. Alloys Compd.JALCEU 437, 298–301.CrossRefGoogle Scholar
Yin, Y., Zhang, G., and Xia, Y. (2002). “Synthesis and characterization of MgO nanowires through a vapor-phase precursor method,” Adv. Funct. Mater.AFMDC610.1002/1616-3028(20020418)12:4<293::AID-ADFM293>3.0.CO;2-U 12, 293–298.3.0.CO;2-U>CrossRefGoogle Scholar
Zeng, X., Pogrebnyakov, A. V., Kotcharov, A., Jones, J. E., Xi, X. X., Lysczek, E. M., Redwing, J. M., Xu, S., Li, Q., Lettieri, J., Schlom, D. G., Tian, W., Pan, X., and Liu, Z.-K. (2002). “In situ epitaxial MgB2 thin films for superconducting electronics,” Nature Mater.NMAACR10.1038/nmat703 1, 35–38.CrossRefGoogle ScholarPubMed
Zhi-An, R., Guang-Can, C., Zhong-xian, Z., Hong, C., Cheng, D., Yong-Ming, N., Shun-Lian, J., and Hai-Hu, W. (2001). “Superconducting properties of MgB2 prepared by high and ambient pressures,” Chin. Phys. Lett.CPLEEU10.1088/0256-307X/18/4/342 18, 589–591.CrossRefGoogle Scholar