Structural and magnetic properties of Cr⁺³ doped nano-structured γ-Fe₂O₃ synthesized by a modified solution combustion technique

Department of Applied Physics, Zakir Husain College of Engineering & Technology, AMU, 202002 Aligarh, India

Corresponding author: ali.phr@gmail.com

Received: 23 November 2010
Accepted: 24 January 2011
Published online: 13 April 2011

Abstract

Chromium doped gamma ferrite nanopowders (16.91 nm to 25.61 nm) of the composition (Fe_2-xCr_xO₃ for x = 0.00, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10) were successfully synthesized by a modified solution combustion method using citric acid as fuel at a temperature as low as 150 °C. The so prepared samples were examined by powder XRD for phase identification and crystallite size determination. The dimensions of particle size as calculated from XRD are in good agreement with those evaluated by transmission electron microscope (TEM). Fourier Transform Infrared (FTIR) analysis was carried out to identify the various chemical bonds present in the system. Magnetic examinations were performed in terms of magnetic susceptibility and hysteresis plots. A decrease in the blocking temperature with the increase of dopant concentration was observed which is explained on the basis of Néel's relaxation theory. A simple model has been suggested to explain the behaviour of hysteresis trends as the function of dopant concentration.