Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-15T00:04:57.430Z Has data issue: false hasContentIssue false
  • English
  • Français

Surface Spin-glass Freezing and Blocking in NiFe2O4 Nanoparticles

Published online by Cambridge University Press:  01 February 2011

Kashif Nadeem  and
Heinz Krenn
Kashif Nadeem
Affiliation:
kashif.nadeem@edu.uni-graz.at, Karl-Franzens university, Institute for Physics, Graz, Austria
Heinz Krenn
Affiliation:
heinz.krenn@uni-graz.at, Karl-Franzens university, Institute for Physics, Graz, Steiermark, Austria
Get access

Abstract

We prepared single-phase nickel ferrite nanoparticles separated by silicon dioxide using sol-gel method with tetraethyl orthosilicate (TEOS) as a precursor for SiO2. The magnetic properties are investigated by using SQUID-magnetometry over a broad temperature range (4.2 – 350 K), magnetic field (2–70,000 Oe) and frequency (0.1 – 1000 Hz) range. The particle size is in the range 8 – 12 nm. Exchange bias and spin disorder appear at the core-shell interface due to broken bonds on the surface. Disorder and core-shell interaction induces spin-glass freezing which is manifested by a low temperature peak in the AC susceptibility well separated from magnetic blocking peak. This low temperature peak is assigned to spin-glass freezing. The proof of spin-glass freezing is managed by zero field cooled/field cooled (ZFC/FC), frequency and DC field dependence of AC susceptibility, low temperature hysteresis loop and time dependent thermoremanent magnetization at different temperatures. All the measurements stated above signify blocking/unblocking at higher temperatures and surface spin-glass freezing at low temperatures. The aim of our work is to contribute to a better understanding of “spin-frozen” magnetic ferrite nanoparticles at diameters 8 – 12 nm which could be important in future for stabilizing the magnetic state of “core-shell”-structured nanomagnets.

Keywords

magnetic propertiescore/shellnanoscale
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1256: Symposium N – Functional Oxide Nanostructures and Heterostructures , 2010 , 1256-N06-06
Copyright
Copyright © Materials Research Society 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1 Tackett, R.J., Bhuiya, A.W. and Botez, C.E., Nanotechnology 20, 445705 (2009).Google Scholar
2 Iglesias, O. and Labarta, A., Phys. Rev. B 63, 184416 (2001).Google Scholar
3 Kodama, R.H., Berkowitz, A.E., and, E.J. McNiff Foner, S., Phys. Rev. Lett. 77, 394 (1996).Google Scholar
4 Kodama, R.H. and Berkowitz, A.E., Phys. Rev. B 59, 6321 (1999).Google Scholar
5 Martinez, B., Obradors, X., Balcells, Ll., Rouanet, A., and Monty, C., Phys. Rev. Lett. 80, 181 (1998).Google Scholar
6 Winkler, E., Zysler, R. D., Mansilla, M. Vasquez, Fiorani, D., Rinaldi, D., Vasilakaki, M., and Trohidou, K.N., Nanotechnology 19, 185702 (2008).Google Scholar
7 Nadeem, K., Traussnig, T., Letofsky-Papst, I., Krenn, H., Brossmann, U., and Würschum, R., J. Alloys Compd. 493, 385 (2010).Google Scholar
8 Nathani, H. and Misra, R.D.K., Mater. Sci. Eng. B 113, 228 (2004).Google Scholar
9 Fiorani, D., Testa, A.M., Lucari, F., D'Orazio, F., and Romero, H., Physica B 320 122–126 (2002).Google Scholar
10 Hohenberg, P.C. and Halperin, B.I., Rev. Mod. Phys. 49, 435 (1977).Google Scholar
11 Mydosh, J.A., Spin Glasses (Taylor & Francis, Washington) (1993).Google Scholar
12 and, K.H. Fischer Hertz, J.A., Spin Glasses (Cambridge University Press, Cambridge) (1991).Google Scholar
13 Binder, K. and Young, A.P., Rev. Mod. Phys. 58, 801 (1986).Google Scholar
14 Brown, W.F. Jr., Phys. Rev. 130, 1677 (1963).Google Scholar
15 Néel, L., Ann. Geophys. 5 99 (1949).Google Scholar