پديد آورنده :
اعظمي، آزاده
عنوان :
بررسي اثر اندازه ي دانه ها بر خواص ساختاري، الكتريكي و مغناطيسي نمونه هايLao.8 Sro.2 Mno3
مقطع تحصيلي :
كارشناسي ارشد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده ي فيزيك
صفحه شمار :
[نه]، 114، [II] ص: مصور، نمودار
يادداشت :
ص. ع: به فارسي و انگليسي
استاد راهنما :
پرويز كاملي
استاد مشاور :
هادي سلامتي
توصيفگر ها :
برهم كنش تبادلي، ابر تبادلي , رفتارفرومغناطيسها , منگناتيها , مغناطو مقاومت TMR، GMR، MR , آناليز SEM
استاد داور :
مرتضي مظفري، مهدي صفا اصفهاني
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتال
چكيده انگليسي :
AbstractIn this project the effect of grain size on structural electrical and magnetic propertiesof La0 8Sr0 2MnO3 were investigated La0 8Sr0 2MnO3 powder and bulk samples wasprepared via solid state reaction method In order to obtain a small particle sizesamples the high energy planetary ball mill was applied employed In this first section of this project the effect of grain size on structural and magneticproperties of the powder La0 8Sr0 2MnO3 was investigated The particle sizedistribution of powders was analyzed by Laser particle size analyzer The resultsshowed that the size can be lowered to some hundred nanometer via ball milling magnetic susceptibility measurements showed that the magnetization and thetransition temperature decline with decreasing of the grain size Examining thechanges of strain with change in grain size with the Williamson hall model showed anincrease in the strain with grain size decrease Annealing effect on strain reductionwas investigated In the second part of this project electrical and magnetic propertiesof bulk samples with various grain sizes were investigated To do this powdersamples with various grain sizes were pressed under 15 ton cm2 pressure and sinteredat 1300 C Magnetic and electrical properties of this samples were investigated withthe use of ac susceptometer increases and closed cycle refrigerator The resultsshowed that by increasing the milling time that grain boundary effect increases andconsequently the magnetization and transition temperature decreases Also resistanceof the samples increases The resistivity of the samples were determined with andwith out the presence of magnetic field It was found that the intrinsic CMR decreases with decreasing the grain size while the extrinsic increases with decreasingthe grain size
استاد راهنما :
پرويز كاملي
استاد مشاور :
هادي سلامتي
استاد داور :
مرتضي مظفري، مهدي صفا اصفهاني
