International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 04 Special Issue: 09 | Sep -2017
p-ISSN: 2395-0072
www.irjet.net
One Day International Seminar on Materials Science & Technology (ISMST 2017) 4th August 2017 Organized by
Department of Physics, Mother Teresa Women’s University, Kodaikanal, Tamilnadu, India
EFFECT OF SYNTHESIS CONDITIONS ON YTTRIUM IRON GARNET (YIG) NANOCRYSTALLINE POWDER VIA SOL GEL METHOD M. Asisi Janifer1, S. Anand2, M. Senthuuran3, S. Pauline4 1,2,3,4 Department
of Physics, Loyola College (Autonomous), Chennai -600034, India *Corresponding author: jenifer92martin@gmail.com ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract: Nanocrystalline powder of pure Yttrium Iron
Garnet (Y3Fe5O12) was synthesized using citric acid as chelating agent. Garnet samples were obtained after calcinations in air at different temperatures for 3 hrs. The Xray Diffraction showed garnet phases of nano ferrites only at high temperatures. The morphological study and elemental composition of the YIG sample was analyzed using High Resolution Scanning Electron Microscope (HR-SEM) and Energy Dispersive X-ray spectrometry (EDX). Dielectric constant and dielectric loss of the nanomaterial at different temperatures were studied with respect to frequency. KEY WORDS: garnet, ferrites, HR- SEM, dielectric studies.
1. INTRODUCTION Magnetic ferrites in nano form are extensively used in wide spectra of applications. Among these nanostructured materials of different shapes and sizes, transition metal ferrite nanoparticles have attracted current research due to their technological applications. Yttrium iron garnet (Y3Fe5O12) is a versatile ceramic material possessing high melting point, large resistivity, better electromagnetic properties, high thermal stability, low thermal expansion, better chemical stability. Also, it has a large Faraday rotation, high initial permeability, high saturation magnetization and strong coercivity. It has attracted considerable attention due to its technological importance in various applications such as microwave devices, acoustic, optical, isolators, circulators, high quality filters, phase shifters, electronics industry and magnetic optical devices.(Majid et al). Majid et al reports that conventional ceramic methods were customarily used for the preparation of garnets which involves high temperatures resulting in loss of fine particle. Nevertheless, in recent years, wet-chemical routes have been developed to address the synthetic difficulties, to prepare fine particles of pure garnet powders. Variety of chemical approaches including sol-gel, co-precipitation and glycothermal synthesis has been reported to prepare submicron to nanocrystalline powders of YIG. Wang Minqiang et al suggest sol-gel method as a widely used technique involving atomic scale mixing that leads to final © 2017, IRJET
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nanocrystals with narrow size distribution. The objective of the present study is to understand the transformations from amorphous to crystalline phase during the formation of YIG powders by cost effective sol gel method. The effects of synthesis parameters on surface morphology and dielectric measurement of YIG are investigated successfully.
2. EXPERIMENTAL PROCEDURE Yttrium nitrate (Y(NO3)3.6H2O, 99.99%) and iron nitrate (Fe(NO3)3.9H2O, 99.99%) for the synthesis of yttrium iron garnet (Y3Fe5O12) were dissolved in the aqueous solution of citric acid (C6H8O7.H2O) the chelating agent. The molar ratio of metal nitrates to citric acid was 1:1. The solution was stirred at 310 rpm for 1 day. The temperature was increased to 80°C with continuous stirring until the formation of gel. The samples in gel form were dried at 110°C for 34hours. The dried powder was ground for 5 hours and finally sintered at 1150°C for 4hours in air furnace. For sample sintered at 950°C the precursors were stirred only for one day without changing other conditions for research purpose. The phase identification and crystalline structure of the prepared samples of Y3Fe5O12 by sol gel method at different temperatures were investigated using X-ray diffractometer (Bruker D8 advance) operated at 40 kV and at 30 mA with CuKα radiation (λ =1.5406 Å). FEI Quanta FEG 200 - High Resolution Scanning Electron Microscope coupled with Energy Dispersive X-ray spectrometry (EDX) was used to examine the morphology and elemental composition. HIOKI LCR meter was utilized for dielectric measurements. It is significant to note that the proposed sol–gel preparation gave reproducible results.
3. RESULTS AND DISCUSSION 3.1. Powder X-ray diffraction: The X-ray diffraction pattern of YIG nanoparticles synthesized by sol–gel method at different temperatures is shown in Fig.1. From the result, it is observed that Y3Fe5O12 samples showed single phase garnet peaks only at high temperatures. No reaction between the starting powders ISO 9001:2008 Certified Journal
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