Preferences help
enabled [disable] Abstract
Number of results
2014 | 125 | 3 | 793-797
Article title

Positron Annihilation in MnFe_2O_4/MCM-41 Nanocomposite

Title variants
Languages of publication
In the paper results of studies of MnFe_2O_4/MCM-41 nanocomposites have been presented. The influence of manganese ferrite loading on changes of porous properties of mesoporous MCM-41 structure was studied by means of N_2 sorption/desorption method and positron annihilation lifetime spectroscopy. Disappearance of the longest-lived ortho-positronium component (τ_5) of pure MCM-41 mesoporous material in the positron annihilation lifetime spectra of MnFe_2O_4/MCM-41 measured in vacuum is a result of either o-Ps quenching or the Ps inhibition mechanism. Filling of pores in the studied nanocomposites by air at ambient pressure causes partial reappearance of the (τ_5) component except for the sample with maximum ferrite content. Both the (τ_5) component lifetime and intensity are suppressed together with increasing MnFe_2O_4 content by chemical quenching and inhibition of Ps formation occur. Observed anti-quenching effect of air is a result of two processes: neutralization of some surface active centres acting as inhibitors and considerably weaker paramagnetic quenching by O_2 molecules.
Physical description
  • [1] P.M. Ajayan, in: Nanocomposite Science and Technology, Eds. P.M. Ajayan, L.S. Schadler, P.V. Braun, Wiley-VCH, Weinheim 2003
  • [2] J. Mohapatra, A. Mitra, D. Bahadur, M. Aslam, Cryst. Eng. Commun. 15, 524 (2013), doi:10.1039/c2ce25957e
  • [3] B. Sahoo, S.K. Sahu, S. Nayak, D. Dhara, P. Pramanik, Catal. Sci. Technol. 2, 1367 (2012), doi:10.1039/c2cy20026k
  • [4] J.S. Beck, J.C. Vartuli, W.J. Roth, M.E. Leonowicz, C.T. Kresge, K.D. Schmitt, C.T.W. Chu, D.H. Olson, E.W. Sheppard, S.B. McCullen, J.B. Higgins, J.L. Schlenker, J. Am. Chem. Soc. 114, 10834 (1992), doi:10.1021/ja00053a020
  • [5] D.M. Schrader, Y.C. Jean, in: Positron and Positronium Chemistry, Eds. D.M. Schrader, Y.C. Jean, Elsevier, Amsterdam 1988, p. 1
  • [6] E.P. Barrett, L.G. Joyner, P.P. Halenda, J. Am. Chem. Soc. 73, 373 (1951)
  • [7] T. Goworek, W. Górniak, J. Wawryszczuk, Nucl. Instrum. Methods Phys. Res. A 321, 560 (1992), doi:10.1016/0168-9002(92)90068-F
  • [8] J. Kansy, Nucl. Instrum. Methods Phys. Res. A 374, 235 (1996), doi:10.1016/0168-9002(96)00075-7
  • [9] J. Rouquerol, D. Avnir, C.W. Fairbridge, D.H. Everett, J.H. Haynes, N. Pernicone, J.D.F. Ramsay, K.S.W. Sing, K.K. Unger, Pure Appl. Chem. 66, 1739 (1994), doi:10.1351/pac199466081739
  • [10] S. Chakrabarti, S. Chaudhuri, P.M.G. Nambissan, Phys. Rev. B 71, 064105 (2005), doi:10.1103/PhysRevB.71.064105
  • [11] S. Bandyopadhyay, A. Roy, D. Das, S.S. Ghugrea, J. Ghose, Philos. Mag. 83, 765 (2003), doi:10.1080/0141861021000042271
  • [12] S. Mitra, K. Mandal, S. Sinha, P.M.G. Nambissan, S. Kumar, J. Phys. D: Appl. Phys. 39, 4228 (2006), doi:10.1088/0022-3727/39/19/016
  • [13] S. Chakraverty, S. Mitra, K. Mandal, P.M.G. Nambissan, S. Chattopadhyay, Phys. Rev. B 71, 024115 (2005), doi:10.1103/PhysRevB.71.024115
  • [14] S. Dannefaer, T. Bretagnon, D. Kerr, J. Appl. Phys. 74, 884 (1993), doi:10.1063/1.354882
  • [15] Y. Kobayashi, K. Ito, T. Oka, K. Hirata, Radiat. Phys. Chem. 76, 224 (2007), doi:10.1016/j.radphyschem.2006.03.042
  • [16] M. Wiertel, Z. Surowiec, M. Budzyński, W. Gac, Nukleonika 58, 245 (2013)
  • [17] S.Y. Chuang, S.J. Tao, J. Chem. Phys. 54, 4902 (1971), doi:10.1063/1.1674769
Document Type
Publication order reference
YADDA identifier
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.