6521

6088

كارشناسي ارشد

ماده چگال

اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك

1390

[شش]، 100ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

پرويز كاملي

هادي سلامتي

15/12/90

مهدي رنجبر، جواد هاشمي فر

1396/10/12

كتابنامه

فيزيك

فيزيك

ID6088

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Preparation and Investigation of Structural and Magnetic Properties of Eu Substituted barium ferrite Fatemeh Khademi f khademi@ph iut ac ir 1390 07 24 Department of Physics Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Dr Parviz Kameli Kameli@cc iut ac irAbstractIn this thesis barium ferrite nano particles were prepared by sol gel method Their structural and magneticproperties of samples have been investigated using thermogravimetric analysis TG DTA X ray powderdiffractometer XRD Fourier transform infrared FTIR scanning electron microscopy SEM Field emissionscanning electron microscopy FESEM ac susceptometer Vibrating sample magnetometer VSM and vectornetwork analyzer At the first part barium ferrite with PVA prepared In order to prepare of this ferrite thestoichiometric amount of iron nitrate Fe NO3 3 barium nitrate Ba NO3 2 polyvinyl alcohol PVA C2H4O n citric acid C6H8O7 H2O and ethylenediaminetetraacetic acid EDTA C10H16N2O8 was used TG DTA curvesshowed that the pure hexagonal phase formed at 800 The XRD patterns with Rietveld analysis indicate theindicated that the M type hexagonal phase formation temperature decreases by the PVA addition The XRD patternsformation of single hexagonal phase and P63 mmc space group The crystallite size of samples was estimated to beabout 40 70 nm by Williamson Hall equation These values are smaller than the crystallite size of the sampleswithout PVA Large particle agglomerations with mean diameter of particles smaller than 1 m were observed inFESEM images FTIR results confirmed the ferrite phase formation In second part the effect of Eu substitution onthe structural and magnetic properties of Ba1 xEuxFe10 5O16 75 x 0 0 0 05 0 1 0 2 0 25 samples was investigated The XRD patterns with Rietveld analysis indicate the formation of single hexagonal phase and P63 mmc spacegroup at 1100 Substituted samples have smaller crystallite size than pure one which demonstrate the graingrowth inhibitor role of Eu SEM images indicated no differences among particle size of samples It is found thatthere are large particle agglomerations too There are not any bound displacement and europium bound in FTIRspectra of substituted samples It is observed that real part of magnetic susceptibility has no change with increasingac field and frequency at room temperature Susceptibility of samples with x doesn t vary remarkably too Themaximum enhancement in coercivity and minimum saturation magnetization was observed in the sampleBa0 75Eu0 25Fe10 5O16 75 The hysteresis loops indicate that doping enhances coercivity and decreases saturationmagnetization The measurements of reflection loss were done at X and Ku band frequency We obtained higherreflection loss for x 0 0 sample in the X band and the ferrite with composition of x 0 1 provides the bestelectromagnetic absorbing properties at Ku band frequency Thus substitution is useful to improve reflection loss atKu band frequency while substitution isn t applicable to enhance the reflection loss at X band frequency Kay words Barium ferrite Sol gel PVA Europium Substituted Magnetic properties Microwave absorption

پرويز كاملي

هادي سلامتي

مهدي رنجبر، جواد هاشمي فر