Magnetic and Electrical Transport Properties of Double Perovskite Sr2FeMoO6Prepared by Sol-Gel Method

Yong-Qing Zhai,Jing Qiao,Zhang Zhang

doi:10.1155/2011/984862

Abstract

With activated carbon for reducing agent, the sol-gel method was used to prepare the giant magnetoresistance materials Sr2FeMoO6, which is the double Perovskite oxide. The structure, morphology, magnetic and electrical transport properties were investigated respectively by x-ray diffraction, scanning electron microscopy and vibrating sample magnetometer. The as-synthesized sample is Sr2FeMoO6with tetragonal crystal structure and I4/mmm space group and unit cell parameter is a = 5.580Å, c = 7.882Å. The primary particles are spherical in shape and the grain size is below 100 nm. The curie temperature is above room temperature and the saturation magnetization is 13.321 A·m2/kg under 1.0 T at room temperature. The sample exhibit typical semiconductor behavior and the conductive mechanism can be described by small polaron variable range hopping model. The room temperature magnetoresistance of the sample under 1.0 T field is up to -10.02%. Moreover, it is found the dosage of citric acid and the amount of reducing agent has great effect on the phase structure and magnetic properties of the samples.

Highlights

Ten years after the discovery of giant magnetoresistance (GMR), the observation at room temperature of a large magnetoresistance in magnetic tunnel junctions gave rise to an increase of the interest for these systems mainly due to their potential applications such as recording media, field sensors or heads for hard drives[1,2].The physical properties of Perovskite La1-xAxMnO3 (A = Ca, Ba, Sr) have been widely studied in the past
The compounds Sr2FeMoO6 reported previously is prepared by the traditional solid state reaction[10], which is carried out at a higher sintering temperature and only the polycrystalline materials with a large grain size are produced
It is well known that Sol–gel method is one of preparation methods for nano-sized materials and homogeneous components can be obtained in relatively low temperature

Summary

Introduction

The compounds Sr2FeMoO6 reported previously is prepared by the traditional solid state reaction[10], which is carried out at a higher sintering temperature and only the polycrystalline materials with a large grain size are produced. Sol-gel method was used to synthesis Sr2FeMoO6 with active carbon as reducing agent. The influence of the dosage of citric acid and the amount of reducing agent on the magnetic properties of the samples was discussed.

Results

Conclusion