Click here to view fulltext PDF

Permanent link:
https://www.ias.ac.in/article/fulltext/pram/061/03/0617-0624

Magnetism; magnetic relaxation; nano-particles; spinel ferrites

DC magnetization measurements are reported in the temperature range 20–100 K on a poly-disperse nano-particle sample of the spinel ferrite Fe_2.9Zn_0.1O₄ with a log-normal size distribution of median diameter 43.6 Å and standard deviation 0.58. Outside a core of ordered spins, moments in surface layer are disordered. Results also show some similarities with conventional spin glasses. Blocking temperature exhibits a near linear variation with two-third power of the applied magnetic field and magnetizationM evolves nearly linearly with logarithm of timet. Magnetic anisotropy has been estimated by analysing theM-logt curve. Anisotropy values show a large increase over that of bulk particle samples. Major contribution to this enhancement comes from the disordered surface spins.

Subhash Chander¹ Sudhish Kumar^{1 2} Anjali Krishnamurthy¹ Bipin K Srivastava¹ V K Aswal^{1 3}

1. Department of Physics, University of Rajasthan, Jaipur - 302 004, India
2. Department of Physics, M.L. Sukhadia University, Udaipur - 313 002, India
3. Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai - 400 085, India

Published

September 2003

Manuscript received

24 April 2002

Manuscript revised

3 February 2003

Accepted

1 April 2003