Increase of the blocking temperature of Fe–Ag granular multilayers with increasing number of the layers

J. Balogh, D. Kaptás, L. Kiss, István Dézsi, Akio Nakanishi, Eamonn Devlin, Marianna Vasilakaki, George Margaris, Kalliopi N. Trohidou

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Multilayers of 0.4 nm Fe and 5 nm Ag with repetition number, n=1, 2, 5, 10 and 20 were prepared by vacuum evaporation onto Si wafer. The blocking temperature was determined by measuring the field cooled and zero field cooled magnetization curves with a SQUID magnetometer and it was found to increase by almost an order of magnitude from around 20 K for the single Fe layer sample up to around 160 K for n=20. Significant increase of the average size of the superparamagnetic Fe grains by increasing the number of the Fe layers was excluded by conversion electron Mössbauer spectroscopy measurements of the paramagnetic state. The role of the dipole–dipole interactions and their interplay with the out-of-plain magnetic anisotropy in the variation of the blocking temperature has been investigated by Monte-Carlo simulations.

Original languageEnglish
Pages (from-to)386-390
Number of pages5
JournalJournal of Magnetism and Magnetic Materials
Publication statusPublished - Mar 1 2016



  • Monte-Carlo simulation
  • Multilayer
  • Mössbauer spectroscopy
  • Superparamagnetism

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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