Studies On Synthesis,Microstructure,Magnetic Properties Of Substituted M-type Ferrites

Nowadays,with the development of science and technology,people's quality of life continues to improving,electronic devices quickly to directions of miniaturization,chip,light,high quality and integrated.As an very important electronic components,the demand for permanent magnet ferrite materials is increasing,the performance requirements are increasingly high.The share of M-type ferrite which is in the permanent ferrite more than 80%,which is divided into three categories,namely strontium,barium,lead ferrite.Therefore,the research of M-type permanent ferrite on the performance has becoming more and more important.In this paper,firstly,the classification of permanent ferrite is introduced;Secondly,the magnetic properties and preparation methods of M-type ferrite are introduced;Finally,Using solid phase reaction method,a sample of doped M type ferrite was prepared.The first experiment,the effect of Y3+ ion substitution Sr2+ on the performance of M-type ferrite SrFe12O19 was studied.The second experiment,the Y3+ion-substituted M-type ferrite Sr0.7-xYxLa0.3Fe12O19 has been studied.The third experiment,the Fe effect of M-type ferrite Sr0.3La0.45Ca0.2FexCo0.4 magnetic poperties was studied.The microstructures were characterized by XRD and SEM.The magnetic propertes were measured by VSM.The specific experimental results are as follows:Using the traditional solid phase reaction method,the Y3+ ion-substituted M-type Sr ferrite was prepared at 1250?.The content of Y3+ ions was studied systematically for Sr1-xYxFe12O19(x= 0,0.02,0.05,0.08,0.1,0.13).The results show:when x>0,the phase of ?-Fe2O3 exists in the sample,and with the increase of Y3+ content,the diffraction of ?-Fe2O3 phase structure peak gradually increased.With the increase of Y3+ substitution,the lattice constant a remained unchanged and the lattice constant c decreased monotonically.In the inside of Y3+ content of different ferrite magnets,which formed a hexagonal sheet structure,and the particle distribution is relatively uniform.With the increase of Y3+ substitution,the saturation magnetization Ms of Sr1-xYxFe12O19 ferrite samples increases first and then decreases,at x= 0.05 which reaching a maximum of 62.74 emu/g,and the coercivity increases with the amount of Y3+ increase.The microstructures and magnetic properties of Sr0.7-xYxLa0.3Fe12O19 ferrite samples prepared were studied by solid-state reaction at 1250?.The results show:the phase of a-Fe2O3 exists in the sample when x>0,and the diffraction peak of?-Fe2O3 phase structure increases with the increase of Y3+ content.When x>0,the lattice constant a remains essentially constant and the lattice constant c decreases monotonically.In the inside of Y3+ content of different ferrite magnets,which formed a hexagonal sheet structure,and the particle distribution is relatively uniform.The saturation magnetization Ms of Sr0.7-xYxLa0.3Fe12O19 ferrite samples decreases with the increase of Y3+ substitution.when x= 0.08,the coercivity Hc decreases monotonically with the increase of x content.The maximum value is 3833 Oe.The samples of Sr0.3La0.45Ca0.25FexO19Co0.4(x= 10.6,10.8,11.0,11.2,11.4,11.6)ferrite were prepared by solid state reaction method at 1390?.Microstructure and magnetic properties.The experimental results show:when x? 11.4,which is a pure phase of M-type ferrite,when x=11.6,which is a large amount of ?-Fe2O3 phase appears.The lattice constant c increases first and then decreases.When x increases from 10.6 to 10.8,the lattice constant c increases from 22.9534 to 22.9727.When x increases from 10.8 to 11.4,the lattice constant c decreases from 22.9727 to 22.9024,and when x=11.6,the lattice constant c becomes smaller.For the lattice constant a,with the change of x,it remains essentially unchanged.In the inside of Y3+ content of different ferrite magnets,which formed a hexagonal sheet structure,and the particle distribution is relatively uniform.With the content of x,the saturated magnetization Ms increases first and then decreases.At x=11.2,The saturation magnetization Ms is maximized,the maximum value is 57.65 emu/g.The coercivity Hc decreases with the content of x which is increasing,When x = 11.6,the coercivity Hc is maximized and the maximum value is 1048 Oe.