[en] The Mossbauer spectra of monodispersed iron oxide nanoparticles with diameters of 4, 7, 9, and 11 nm have been measured between 4.2 and 315 K and fitted within the formalism for stochastic fluctuations of the hyperfine Hamiltonian. In this model, the hyperfine field is assumed to relax between the six +/- x, +/- y, and +/- z directions in space with a distribution of relaxation rates that is temperature dependent. Muon spin relaxation measurements have been carried out on the 9 nm particles between 4.2 and 295 K. Both techniques reveal three regimes in the magnetic dynamics of these nanoparticles. In the low-temperature regime, between 4.2 and similar to 30 K, the nanoparticle magnetic moments are blocked and a spin-glass-like state is observed with nearly static hyperfine fields, as is indicated by the well resolved magnetic Mossbauer spectra and the slow exponential decay of the muon asymmetry functions. In the high-temperature regime, above similar to 125 K, the nanoparticle magnetic moments and, hence, the hyperfine fields, relax rapidly and a typical thermally activated superparamagnetic behavior is observed, as is indicated by the Mossbauer doublet line shape and the muon asymmetry functions that are unquestionably characteristic of monodispersed nanoparticles. In the intermediate regime between similar to 30 and 125 K, the Mossbauer spectra are the superposition of broad sextets and doublets and the muon asymmetry functions have been fitted with a sum of two terms, one relaxing term similar to that observed at and above 125 K and one term characteristic of static local fields. Hence, in this intermediate regime, the sample is magnetically inhomogeneous and composed of nanoparticles rapidly and slowly relaxing as a result of interparticle interactions. The magnetic anisotropy constants determined from both the Mossbauer spectral and magnetic susceptibility results decrease by a factor similar to 4 with increasing diameter from 4 to 22 nm and increase linearly with the percentage of iron(III) ions present at the surface of the nanoparticles. The interparticle interaction energy is estimated to be between 89 and 212 K from the temperature dependence of the magnetic hyperfine field measured on the 9 nm nanoparticles.
Disciplines :
Physics
Author, co-author :
Rebbouh, Leila
Hermann, Raphaël ; Université de Liège - ULiège > Département de physique > Département de physique
Grandjean, Fernande ; Université de Liège - ULiège > Département de physique > Département de physique
Hyeon, Taeghwan
An, Kwangjin
Amato, Alex
Long, Gary J
Language :
English
Title :
Fe-57 Mossbauer spectral and muon spin relaxation study of the magnetodynamics of monodispersed gamma-Fe2O3 nanoparticles
Publication date :
2007
Journal title :
Physical Review. B, Condensed Matter and Materials Physics
ISSN :
1098-0121
eISSN :
1550-235X
Publisher :
Amer Physical Soc, College Pk, United States - Maryland
G. Schmid, Nanoparticles: From Theory to Application (Wiley-VCH, Weinheim, 2004);
K. J. Klabunde, Nanoscale Materials in Chemistry (Wiley-Interscience, New York, 2001);
A. P. Alivisatos, Science SCIEAS 0036-8075 10.1126/science.271.5251.933 271, 933 (1996);
M. P. Pileni, Nat. Mater. NMAACR 1476-1122 10.1038/nmat817 2, 145 (2003).
S. Sun, C. B. Murray, D. Weller, L. Folks, and A. Moser, Science SCIEAS 0036-8075 10.1126/science.287.5460.1989 287, 1989 (2000);
D. E. Speliotis, J. Magn. Magn. Mater. JMMMDC 0304-8853 10.1016/S0304-8853(98)00399-0 193, 29 (1999).
T. Hyeon, S. Seong Lee, J. Park, Y. Chung, and H. Bin Na, J. Am. Chem. Soc. JACSAT 0002-7863 123, 19798 (2001).
J. Park, K. An, Y. Hwang, J. G. Park, H. J. Noh, J. Y. Kim, J. H. Park, N. M. Hwang, and T. Hyeon, Nat. Mater. NMAACR 1476-1122 10.1038/nmat1251 3, 891 (2004).
J. Park, E. Lee, N. M. Hwang, M. Kang, S. C. Kim, Y. Hwang, J. G. Park, H. J. Noh, J. Y. Kim, J. H. Park, and T. Hyeon, Angew. Chem., Int. Ed. ACIEF5 1433-7851 10.1002/anie.200461665 44, 2872 (2005).
E. Tronc, Nuovo Cimento Soc. Ital. Fis., D NCSDDN 0392-6737 10.1007/BF02458890 18D, 163 (1996);
E. Tronc, J. Magn. Magn. Mater. JMMMDC 0304-8853 10.1016/S0304-8853(00) 00369-3 221, 63 (2000);
J. L. Dormann, D. Fiorani, and E. Tronc, in Advances in Chemical Physics, edited by, I. Prigogine, and, S. A. Rice, (Wiley, New York, 1997), Vol. 98, p. 283.
S. Mørup, F. Bødker, P. V. Hendriksen, and S. Linderoth, Phys. Rev. B PRBMDO 0163-1829 10.1103/PhysRevB.52.287 52, 287 (1995).
Ö. Helgason, H. K. Rasmussen, and S. Mørup, J. Magn. Magn. Mater. JMMMDC 0304-8853 10.1016/j.jmmm.2005.09.036 302, 413 (2006).
L. Theil Kuhn, K. Lefmann, C. R. H. Bahl, S. Nyborg Ancona, P. A. Lindgård, C. Frandsen, D. E. Madsen, and S. Mørup, Phys. Rev. B PRBMDO 0163-1829 10.1103/PhysRevB.74.184406 74, 184406 (2006).
T. Jonsson, J. Mattsson, C. Djurberg, F. A. Khan, P. Nordblad, and P. Svedlindh, Phys. Rev. Lett. PRLTAO 0031-9007 10.1103/PhysRevLett.75.4138 75, 4138 (1995).
T. Jonsson, P. Nordblad, and P. Svedlindh, Phys. Rev. B PRBMDO 0163-1829 10.1103/PhysRevB.57.497 57, 497 (1998).
C. Djurberg, P. Svedlindh, P. Nordblad, M. F. Hansen, F. Bødker, and S. Mørup, Phys. Rev. Lett. PRLTAO 0031-9007 10.1103/PhysRevLett.79. 5154 79, 5154 (1997).
J. L. Dormann, L. Spinu, E. Tronc, J. P. Jolivet, F. Lucari, F. D'Orazio, and D. Fiorani, J. Magn. Magn. Mater. JMMMDC 0304-8853 10.1016/S0304-8853(98) 00135-8 187, L139 (1998).
D. Fiorani, J. Magn. Magn. Mater. JMMMDC 0304-8853 10.1016/S0304-8853(98) 00694-5 196, 143 (1999).
P. Jönsson, T. Jonsson, J. L. Garcia-Palacios, and P. Svedlindh, J. Magn. Magn. Mater. JMMMDC 0304-8853 10.1016/S0304-8853(00)00557-6 222, 219 (2000).
J. S. Lord, J. Phys.: Conf. Ser. JPCSDZ 1742-6588 10.1088/1742-6596/17/1/ 014 17, 81 (2005).
M. Blume, Phys. Rev. PHRVAO 0031-899X 10.1103/PhysRev.174.351 174, 351 (1968).
S. Dattagupta and M. Blume, Phys. Rev. B PLRBAQ 0556-2805 10.1103/PhysRevB.10.4540 10, 4540 (1974).
R. P. Hermann, V. Keppens, P. Bonville, G. S. Nolas, F. Grandjean, G. J. Long, H. M. Christen, B. C. Chakoumakos, B. C. Sales, and D. Mandrus, Phys. Rev. Lett. PRLTAO 0031-9007 10.1103/PhysRevLett.97.017401 97, 017401 (2006).
R. E. Vandenberghe and E. De Grave, in Mössbauer Spectroscopy Applied to Inorganic Chemistry, edited by G. J. Long and F. Grandjean (Plenum, New York, 1989), Vol. 3, p. 59.
A. D. Arelaro, A. L. Brandl, E. Lima, Jr., L. F. Gamarra, G. E. S. Brito, W. M. Pontuschko, and G. F. Goya, J. Appl. Phys. JAPIAU 0021-8979 10.1063/1.1853931 97, 10J316 (2005).
G. K. Shenoy, F. E. Wagner, and G. M. Kalvius, in Mössbauer Isomer Shifts, edited by, G. K. Shenoy, and, F. E. Wagner, (North-Holland, Amsterdam, 1978), p. 49.
S. Mørup, C. A. Oxborrow, P. V. Hendriksen, M. S. Pedersen, M. Hanson, and C. Johansson, J. Magn. Magn. Mater. JMMMDC 0304-8853 140-144, 409 (1995).
S. F. J. Cox, J. Phys. C JPSOAW 0022-3719 10.1088/0022-3719/20/22/005 20, 3187 (1987).
I. A. Campbell, A. Amato, F. N. Gygax, D. Herlach, A. Schenck, R. Cywinski, and S. H. Kilcoyne, Phys. Rev. Lett. PRLTAO 0031-9007 10.1103/PhysRevLett.72.1291 72, 1291 (1994).
A. Schenck, Muon Spin Rotation Spectroscopy (Adam Hilger, Bristol 1985).
T. J. Jackson, J. Phys.: Condens. Matter JCOMEL 0953-8984 10.1088/0953-8984/12/7/321 12, 1399 (2000).
F. Bødker, M. F. Hansen, C. B. Koch, K. Lefmann, and S. Mørup, Phys. Rev. B PRBMDO 0163-1829 10.1103/PhysRevB.61.6826 61, 6826 (2000).
M. F. Hansen, C. B. Koch, and S. Mørup, Phys. Rev. B PRBMDO 0163-1829 10.1103/PhysRevB.62.1124 62, 1124 (2000).
F. Bødker and S. Mørup, Europhys. Lett. EULEEJ 0295-5075 10.1209/epl/i2000-00426-2 52, 217 (2000).
S. Mørup and C. W. Ostenfeld, Hyperfine Interact. HYINDN 0304-3843 10.1023/A:1015516828586 136, 125 (2001).
S. Linderoth, P. V. Hendriksen, F. Bødker, S. Wells, K. Davies, S. W. Charles, and S. Mørup, J. Appl. Phys. JAPIAU 0021-8979 10.1063/1.356902 75, 6583 (1994).
J.-R. Jeong, S.-C. Shin, S.-J. Lu, and J.-D. Kim, J. Magn. Magn. Mater. JMMMDC 0304-8853 10.1016/j.jmmm.2004.09.129 286, 5 (2005).
D. Fiorani, A. M. Testa, F. Lucari, F. D'Orazio, and H. Romero, Physica B PHYBE3 0921-4526 10.1016/S0921-4526(02)00659-2 320, 122 (2002).
D. Predoi, V. Kuncser, and G. Filoti, Rom. Rep. Phys. RORPED 1221-1451 56, 373 (2004).
S. Mørup, J. Magn. Magn. Mater. JMMMDC 0304-8853 10.1016/0304-8853(83)90350-5 37, 39 (1983).
Q. A. Pankhurst, D. H. Ucko, L. Fernandez Barquin, and R. Garcia Calderon, J. Magn. Magn. Mater. JMMMDC 0304-8853 10.1016/S0304-8853(03)00464-5 266, 131 (2003).