Size effect on the magnetic properties of oleic acid stabilized substrate free BiFeO₃ nanocrystals

¹ Department of Physics, Visva-Bharati, Santiniketan 731 235, India
² Department of Condensed Matter Physics and Material Sciences, S.N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India

^a e-mail: sk_mandal@hotmail.com

Received: 2 January 2015
Revised: 13 March 2015
Accepted: 16 March 2015
Published online: 24 April 2015

Abstract

We report here on the unique synthesis of BiFeO₃ (BFO) nanocrystals of different size by using oleic acid as a capping agent and investigate the structural and magnetic properties. Oleic acid is found to be a good stabilizing agent to obtain different crystal size and distributions of BFO nanocrystals. Structural characterizations by X-ray diffraction (XRD) reveal the phase purity of all the samples. The BFO nanocrystals display strong size dependent magnetic properties showing increase in both magnetization (M_s) as well as in coercive field (H_c) with decreasing the crystal size due to the size confinement effect as well as change in magnetocrystalline anisotropy. The smallest BFO nanocrystal of size ~12 nm shows remarkably high (8.17 emu/g) magnetization value compared to previous reports. The results obtained here will be of immense important for advanced applications in electromagnetic devices.