Studies on structural optical and magnetic properties of transition metals cd and ag and rare earth elements la and doped zno nanograins

Abstract

Transition Metals And Rare Earth Elements Doped Zinc Oxide Has Sparked A Great Research Interest And Scientific Activity In Recent Years. The Study Of Zinc Oxide As A Dilute Magnetic Semiconductor With Transition Metal Oxide And Rare Earth Metals Is Now Becoming A Challenging And Promising Area Of Research. The Main Objective Of The Thesis Is To Synthesis Cd/Ag Doped And La and Y Codoped Zno Nanograins By Solgel Auto Combustion Route Without Using Hazardous Reagents. The Structural, Optical And Magnetic Properties Have Been Explored For The Prepared Nanograins. Zinc Oxide Doped With Cadmium And Rare Earth Elements (Lathanum And Yttrium) Synthesized By Solgel Auto Combustion Route And Annealed At 900°C For 5 Hours. The Influence Of Cd, La And Y On Structural, Morphological, Optical Properties And Magnetic Properties Of Zno Are Discussed. The XRD Analysis Reveals That The Addition Of Rare Earth Impurity Decreases The Particle Size Of Zncdo. La Doped Zncdo Has The Least Particle Size Among The Samples Of Zncdo And Rare Earth Doped Zncdo. XRD Results Also Confirmed The Hexagonal Wurtzite Structure For Zno. The Morphological Changes Due To The Addition Of Rare Earth Impurities Have Been Found. Samples Of La Doped Zncdo Shows A Pillar Like Morphology. The Hexagonal Structures Are Prominently Seen In The SEM Micrographs Of The Samples Of Zncdo. The UV Visible Spectral Analyses Show That The Bandgap Reduces When Zncdo Is Doped With The Rare Earth Impurities. The FTIR Studies Revealed The Presence Of Different Stretching And Bending Modes Of Zn O. The Photoluminescence Spectra Show The Broad Spectrum In Visible Region Exhibited By Zno And A Scanty UV Emission. The UV Emission Of Rare Earth Doped Samples Decreases Due To The Destruction In The Crystal Structure. The Rare Earth Doped Zncdo Shows A Small Peak In Green Emission That Decreases When Rare Earth Impurities Are Doped. There Is A Uniform Spectral Response Other Than A Small Gaussian Like Green Peak. The Overall Optical Analyses Show That The Samples Can Be Used In Optoelectronic Applications To Work In The Visible Region. The EPR Spectrum Exhibits The Split Into Six Hyperfine Structure Due To Traces Of Mn2+ Inherently Present In Zno Lattice Along With A Sharp Single Characteristic Peak Of Zno At G=1.96. The EPR Intensities Of Doped Zno Decreases And The Paramagnetic Susceptibility Calculated From EPR Spectra Increases With Addition Of Dopants Due To Lattice Distortion. The Linearity Of EPR Signal Intensity With PL Spectral Intensity Confirmed The Intrinsic Defects Due To Oxygen Vacancies In The Doped Zno Nanograins. The Magnetic Properties From VSM Studies Exhibited The Transformation From Ferromagnetic To Paramagnetic Behavior With Rare Earth Doped Zno Nanograins. These Results Reveal That The Rare Earth Doped Samples Are Promising Material For Advanced Functional Devices. newline