ساخت و مطالعه نانو ذرات فريت منگنز (MnFe2O4) و بررسي تاثير افزايش سيليكا ﴿Sio2 ﴾بر خواص مغناطيسي نانو ذرات

چكيده انگليسي :

133 Fabrication and Study of Manganese Ferrite Nanoparticles MnFe2O4 and Investigation of the Effects of Silica SiO2 Doping on the Magnetic Properties of Nanoparticles Seyed Ebrahim Aalaye e aalaye@gmail com March 14 2011 Department of Physics Isfahan University of technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Dr Parviz Kameli Mail kameli@cc iut ac ir Abstract In this study powders of manganese ferrite nanoparticles MnFe2O4 which are having spinel structure was prepared The method used for preparing nanoparticles is sol gel and this method is easy and quick method This study consists of three parts In the first part we have prepared the manganese ferrite nanoparticles with different pH In the second part of our study we have studied the effect of reducing the interactions by adding silica SiO2 to compound In the third part we have studied the effect of increasing interactions with apply pressure In this study several tools for feature detection and investigation of structural and magnetic properties of samples is used that includes 1 X ray diffraction analysis XRD 2 infrared spectroscopy analysis FTIR 3 Thermal analysis of samples TG DTA 4 Vibrating Sample Magnetometer VSM 5 Ac magnetic Susceptibility 6 transmission electron microscopy TEM and 7 field emission scanning electron microscopy FESEM Raw materials used in the first part consist of iron and manganese nitrate citric acid distilled water and ammonia The pH of primary solution that combined of raw materials is two and for preparing the solutions with upper pHs we add ammonia to this solution so we prepared samples with pHs 4 6 and 8 Using the analysis results of different tools we have observed that the manganese ferrite nanoparticles with pH of 2 treated with interaction superparamagnetism We have observed that with change of pH the size of the nanoparticles are increased so that for sample with pH of 2 the size of nanoparticles is 6 nm and for another samples the size of nanoparticles is approximately 15 nm The sample with pH of 2 hasn t any residual but other samples have a little residual In the second part for injection of silica to the mixture we should prepare another solution Therefor we made another solution of tetraethyl silica TEOS and ethanol and be added to the previous solution It observed that with adding the silica to compound the magnetic properties of samples and interaction between nanoparticles decrease which was expected With increasing the nonmagnetic matter silica the size of nanoparticles decreased and to this reason observed magnetic properties decreased As we have seen these samples don t have any residual so these samples have superparamagnetism behavior too In the third part we pressed some of prepared samples in the previous parts with different pressures and we observed increasing of the pressure increase the interactions between the nanoparticles and it was expectable All of the samples pressed without silica have interacting superparamagnetic behavior and with increasing the pressure the size of interactions increase It observed in the samples with silica that with make of pressure doesn t have more changes in interactions between nanoparticles This behavior is because that the nanoparticles are floated in the silica lattice and these nanoparticles can t close together and to this reason the interactions between them don t have more change Key words Ferrite Manganese Superparamagnet Silica Press pH

اعلائي، ابراهيم

ساخت و مطالعه نانو ذرات فريت منگنز (MnFe2O4) و بررسي تاثير افزايش سيليكا ﴿Sio2 ﴾بر خواص مغناطيسي نانو ذرات

ابرپارامغناطيس , فشار