Preparation Of Ni-Mg-Co Ferrite And Doping Of Ni-Cu-Co Ferrite And Their Magnetic Properties

Magnetic materials play an extremely important role in the rapid development of the information age,and is an important functional material,in the field of materials science has attracted much attention.In this paper,by using the sol-gel from burning the preparation methods of the preparation of magnesium nickel cobalt and nickel,copper and cobalt ferrite nanoparticles for magnetic materials has opened up many new uses,since it has large specific surface area,low dielectric constant and high magnetic loss and other characteristics are widely used in various fields,such as magnetic resonance imaging contrast agents in the biomedical field,the magnetic power electronic data storage,antenna and the high speed digital tape,catalyst,magnetic liquid and microwave absorber,etc.In addition,they are favored by scientific researchers because of their low cost,simple process and high stability.The magnetic property and structure of ferrite magnetic materials will vary due to annealing conditions,the pH value of the precursor and other external factors,and will also be affected by the particle spacing and particle size of prepared samples.In this work,we prepared Ni-Mg-Co and Ni-Cu-Co ferrite nanoparticles by sol-gel self-combustion,analyzed and studied their structure and magnetic properties.The following are the main three parts of the work:1.Nano-ferrite powder with chemical composition Ni_0.2Cu_0.1Co_0.7Fe_2-xCe_xO₄?x=0.0,0.025,0.05,0.075,0.1?was prepared using the sol-gel self-combustion method.The sintering temperature was 950°C.Various technical characteristics indicate that all the samples have a spinel structure.Ferrite nanoparticles were observed to be spherical and cubic.When the doping content of Ce³⁺ions is x=0.025,the sample has the best magnetic properties.It has the largest squareness?Mr/Ms?and coercivity rectangularity?S*?.Experimental data show that a small amount of Ce³⁺ion doping can improve the magnetic properties of the sample.2.Ni_0.2Mg_xCo_0.8-xFe₂O₄ nanocrystals were successfully synthesized by the sol-gel method.The structure and magnetic properties of undoped and Mg-substituted Ni-Co ferrites have been systematically studied.The synthesized sample was confirmed by XRD analysis to form a single-phase cubic spinel structure with crystals between 48 and50 nm.The lattice constant is inversely proportional to the concentration of magnesium ions.The results of FTIR spectroscopy showed that a spinel structure was formed.The spherical cubic microcrystalline structure in the sample is shown in the TEM image.EDX analysis confirmed that the synthesized ferrite has a pure phase structure.Both Ms and Mr at room temperature decreased with increasing Mg²⁺ion concentration.At the same time,the coercive force decreased from 1032.16 Oe to 378.50 Oe with the increase of Mg²⁺ion concentration.This also indicates that Mg-substituted Ni-Co nano-ferrite is a multi-iron material with low magnetic properties.The good crystallinity and magnetic stability of cubic spinel structure samples are also shown by the increase in the peak height of dM/dH at Hm.3.Ni_0.2Mg_0.2Co_0.6Fe₂O₄ ferrite nanoparticles were prepared by a sol-gel self-combustion method.S5-S10 samples were prepared by different sintering temperature annealing methods.XRD,FTIR,SEM and VSM were used to study the structure and magnetic properties of the samples.XRD analysis confirmed that all samples were cubic spinel structures.The particle size of the sample was calculated by Scheler's equation from 51nm to 135nm.The annealing temperature increased from500°C to 1000°C,the peak intensity of the six samples increased,the crystallinity and particle size of the samples increased significantly,Hc decreased,Ms,Mr and Mr/Ms increased first and then decreased.Compared with other samples,the saturation magnetization?59.03 emu/g?,the residual magnetization?30.65 emu/g?and the rectangularity?0.519?of the sample at the annealing temperature of 800°C were the highest.The increased peak height of dM/dH at Hm indicates that samples with cubic spinel structure have good crystallinity and magnetic stability.