Effects of the Fe³⁺/Sr²⁺ molar ratio on the exchange-coupling of the composite and single-phase SrFe₁₂O₁₉

Anhui Key Laboratory of Information Materials and Devices, School of Physics and Materials Science, Anhui University, Hefei 230039, People’s Republic of China

^a e-mail: yqma@ahu.edu.cn

Received: 8 July 2012
Revised: 9 December 2012
Accepted: 21 January 2013
Published online: 20 March 2013

Abstract

It has been systematically investigated about the magnetic properties of the composite and single-phase SrFe₁₂O₁₉ prepared with the precursor of different Fe³⁺/Sr²⁺ molar ratios of 12:1, 11:1 and 10:1, respectively. With increasing the calcinations temperature, the coercivity of all samples decreases which can be determined by the stress model. The δm(H) results indicate that the intergrain exchangecoupling interaction exists both in composite and in single-phase SrFe₁₂O₁₉, resulting in the remanence magnetization enhancement, and the magnetostatic interaction become dominant in the samples with higher calcinations temperatures. The irreversible susceptibilities χ_irr(H) curves show that there may exhibit the exchange-spring behavior in the composite SrFe₁₂O₁₉ with more soft magnetic γ-Fe₂O₃, and the irreversible switching field may be qualitatively used to determine the coercivity magnitude.