Electrical And Magnetic Transport Properties Of La_0.7Ca_0.2Sr_0.1MnO₃/Fe_x(SiO₂)_1-x Composites

In the nanostructure material, Fe-base nano-material is one of the most important kinds of material. For Fe has always been a key material in human history. While in the GMR/CMR material, manganites perovskite gets a lot of focus in recent years.In this thesis, we used mechanical alloying method to fabricate the Fe_x(SiO₂)_1-x (0.050.7Ca_0.2Sr_0.1MnO₃. Then we made the two different kind of material together and researched their structure, surface topography, electric and magnetic properties. This thesis has been divided into five chapters.In the first chapter, the history of nanostructed material and CMR material was depicted. Also their recent development and the future of these two kinds of materials were illustrated. Then we cast the purpose of this thesis.In the second chapter, two different method, mechanical alloying and solid state reaction, for preparing our research objects were introduced. Meanwhile we also introduced some ways to measure our sample, eg: x-ray diffraction.In the third chapter, we fabricated a serial of Fe_x(SiO₂)_1-x samples for the different x value. And their properties were researched.In the fourth chapter, we add Fe_x(SiO₂)_1-x into La_0.7Ca_0.2Sr_0.1MnO₃ to form a kind of material. Then research its structure, surface topography, electric and magnetic properties. The fifth chapter was the conclusion for the whole thesis.