| Biography | |
|---|---|
 Prof. Ravinder Dachepalli Osmania University, Telangana, India |
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| Title: Crystal chemistry, Structural, Electrical, dielectric and magnetic properties Co-Er nano-particles | |
| Abstract: Synthesis of Cobalt-Erbium nano-ferrites with formulation CoErxFe2-xO4 (x = 0, 0.005, 0.010, 0.015, 0.020, 0.025, and 0.030) using technique of citrate-gel auto-combustion was done. Characterization of prepared powders was done by using XRD, EDS, FESEM, VSM, FTIR Spectroscopy, DC resistivity and dielectric properties respectively. XRD Rietveld Analysis, SEM, TEM and EDAX analysis were taken up in studying spectral, structural, magnetic and electrical properties. XRD pattern of CEF nano particles confirm single phase cubic spinal structure. The structural variables given by lattice constant (a), lattice volume (v), average crystallite size (D) and X-ray density(dx), Bulk density (d), porosity (p), percentage of pore space (P%), surface area (s), strain (ε), dislocation density (δ), along with ionic radii, bond length and hoping length were calculated. SEM and TEM results reveal homogeneous nature of particles accompanied by clusters having no impurity pickup. TEM analysis gives information about particle size of nanocrystalline ferrite while EDAX analysis confirm elemental composition. Emergence of two arch shaped frequency bands (v1andv2) that represent vibrations at tetrahedral site (A) and octahedral site (B) was indicated by spectra of FTIR. The samples electrical resistivity (DC) was measured between 300C -6000C with Two probe method. Dielectric parameters were studied at room temperature between 1Hz to 8MHz frequency range. XRD Rietveld analysis confirm crystallite size lying between 20.84nm-14.40nm while SEM analysis indicate formation of agglomerates and TEM analysis indicate particle size ranging between 24nm-16 nm. DC Electrical measurements indicate continuous decrease in resistivity with increasing temperature while increasing doping decreases curie temperature. Magnetization measurements indicated increasing Er3+ content in cobalt ferrites decreases magnetization from 60emu/g to 42emu/g while coercivity decreases to (18990) as compared to CoFe2O4(18998) in cobalt ferrites with doping. The present study investigates the effect of different compositions of Er3+ replaced for Fe on structure, dielectric, magnetic properties and electrical resistivity of cobalt ferrites. | |
| Biography: Prof. Ravinder Dachepalli is working as a professor in Physics, Department of Physics, Osmania University, Telangana, India since 36 years and his research work on magnetic and electrical properties of nano-ferrites,magnetic materials, ferrites, Energy materials, thin films, GMR materials, Cu-Co alloy thin films and nano-materials( Nanotechnology) by pulsed laser deposition, sol gel, citrate precursor method and electro deposition. To his credit he has published 250 research papers in an International Journals( Applied Physics letters, JMM, J alloys and compounds, Journal of Nano-chemistry, Bulletin of Materials, Materials letters, Materials physics and chemistry, Sciences, Journal of applied physics, Journal of American ceramics society, Nano-structures in chemistry etc. He has been awarded Young Scientist award received by Dr. Abdual Kalam (former president of India), for outstanding contributions in the field of science and Technology, UGC career award, Boyscast fellowship by DST( Department of science and technology, Government of India, JSPS fellowship Japan and Royal Society fellowship, UK. Prof. Ravinder also visited USA, UK, Sweden, Ireland, Canada, Singapore and Japan for Collaborative Research and conference papers presentation and invited talks. Recently Prof. Ravinder, has been been recognitioned for world ranking 2% Indian Scientist for outstanding contribution in the field of materials, Science and Technology based on the research contribution. This was recognitioned by Standford University Scientists on World Wide Survey. Prof. D. Ravinder,Department of Physics,Osmania University Hyderabad-500007, Telangana State India E-mail: ravindergupta28@rediffmail.com Mobile No: 9246162228 | |
