Journal of Surface Science and Technology

B. K. Nath ¹, P. K. Chakrabarti ², S. Das ³, U. Kumar ⁴, P. K. Mukhopadhyay ⁴, D. Das ¹

Affiliations
1 IUC-DAEF, Bidhannagar, Kolkata 700 098, IN
2 Department of Physics, Asutosh College, Kolkata 700 026, IN
3 Department of Physics, Jadavpur University, Kolkata 700 032, IN
4 S. N Bose National Centre for Basic Sciences, Bidhannagar, Kolkata 700 098, IN

Abstract

Nanoparticles of zinc substituted Mg-ferrite (Mg_(1-x)Zn_xFe₂O₄, x = 0.70 and 0.85) with well-developed spinel phases have been prepared by standard co-precipitation method. Single-phase ferrite with a spinel structure began to form at a relatively lower temperature (∼200 °C). X-ray diffratometry and ⁵⁷Fe Mossbauer effect measurements were carried out to characterize Mg-Zn-ferrite nanoparticles. The particle sizes obtained from Sherrer equation lie in the range, 6.4 nm to 25.6 nm. Mossbauer measurements at room temperature and down to 20 K clearly indicate the presence of superparamagnetic particles in all the samples. Superparamagnetic relaxation was observed at room temperature even for larger particle size of the samples and this may be due to the weakening of A-B exchange interaction in ferrite lattice due to replacement of Fe³⁺ ions in tetrahedral sites by Zn²⁺ ions.

Keywords

Spinel Ferrites, Superparamagnetism, Mosshauer Spectroscopy, Relaxation Pacs No. : 75.50 Tt, 76.80+y, 75.30 Cr.

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