Positron Annihilation in MnFe_2O_4/MCM-41 Nanocomposite

• Authors: M. Wiertel , Z. Surowiec , W. Gac , M. Budzyński
• Languages of publication: EN

Abstracts

EN

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.

Keywords

EN

78.70.Bj; 34.80.Lx; 78.67.Bf; 62.23.Pq; 68.43.-h; 75.50.Gg; 78.47.D-

Discipline

• 68.43.-h: Chemisorption/physisorption: adsorbates on surfaces
• 78.70.Bj: Positron annihilation(for positron states, see 71.60.+z in electronic structure of bulk materials; for positronium chemistry, see 82.30.Gg in physical chemistry and chemical physics)
• 75.50.Gg: Ferrimagnetics
• 78.67.Bf: Nanocrystals, nanoparticles, and nanoclusters
• 62.23.Pq: Composites (nanosystems embedded in a larger structure)
• 78.47.D-: Time resolved spectroscopy (>1 psec)
• 34.80.Lx: Recombination, attachment, and positronium formation

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2014
• Volume: 125
• Issue: 3
• Pages: 793-797

Dates

published

2014-03

Contributors

author

M. Wiertel

• Department of Nuclear Methods, Faculty of Mathematics, Physics and Computer Science Maria Curie-Skłodowska University, pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland

author

Z. Surowiec

• Department of Nuclear Methods, Faculty of Mathematics, Physics and Computer Science Maria Curie-Skłodowska University, pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland

author

W. Gac

• Department of Chemical Technology, Faculty of Chemistry, Maria Curie-Skłodowska University pl. M. Curie-Skłodowskiej 3, 20-031 Lublin, Poland

author

M. Budzyński

• Department of Nuclear Methods, Faculty of Mathematics, Physics and Computer Science Maria Curie-Skłodowska University, pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland

References

• [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

Identifiers

DOI

10.12693/APhysPolA.125.793