1.1 INTRODUCTION TO FERRITE:
Magnetic materials play an important .It has many technological and electrical applications in the present civilization .1Ferrites have relevant value in the class of ceramic oxides which exhibit magnetic and electrical properties .2Ferrites are ferromagnetic material which have double oxide of iron with other materials.(K).Ferrites have widely used in modern civilization .The main cause of widely used of ferrites in the magnetic field is the ability to the outfitter material with outstanding magnetic properties which compared to bulk system because of their construction. 1 The characteristics of ferrites depend on the chemical composition cation distribution and the formulation of preparation method. Ferrites are significant branch of ferromagnetic which are most important material both application and theoretical view of point. Ferrites have high resistivity which varies from 102 to 1010 ohm-cm which are 15 times higher than that of iron. Because of these magnificent properties of ferrites ,it make them more demandable for high frequency application .(K) Ferrites have high frequency , low heat resistance, high corrosion resistor ,which make them more demandable for electromagnetic devices .The ferrites which behave as soft magnetic materials due to their exchange interaction among the cation of polyhedral sites. The rare earth cation have 4f orbital totally screened by 5s and 5p orbital these play an important role to explain electrical and magnetic properties of ferrites. The rare earth substituted ferrites have an important contribution in modern communication and electronic devices.3Nano-crystalline ferrites are most important because of their unique electric, dielectric, magnetic and optical properties which have a remarkable application both theoretical and technological sides. In ferrites strong degrease in the saturation magnetization (Ms ) and of coercivity (Hc ) in comparison to the bulk modulus have been studied. Ferrites nanoparticles are widely used in electronics, bioprocessing magnetic resonance imaging Ferro fluids. Spinel soft ferrites are specially important because they are relatively inert and their properties can be tailored by chemical multiplication .In recent years number of chemical and physical methods include mechanical milling, severe plastic deformation consolidation and inert gas condensation .4 Spinel ferrite have a significant application in electrical components such as memory devices and microwave devices and these ferrites have wide range frequency because of their high resistivity and loss behavior .5 Ferrites are used as high purity metal oxide which are prepared by ceramic technology .In these method the ferrites which are prepared are bulk material .In the modern nanotechnology, by using many different methods ferrites have been made Nano size particle.(Chapter 7,5).
1.2: IMPORTANCE OF FERRITES
Ferrites have many important application in magnetic materials at higher frequency, lower price, greater heat resistance and higher corrosion resistance. These materials have many technological importance at variety of areas ,the use of ferrites have increased day by day .Because of their good magnetic properties and high electrical resistivity over a wide range frequency which start from a few hundred Hz to several GHz , polycrystalline ferrites have great importance in magnetic field . Among the soft magnetic materials .They have high magnetic permeability and low magnetic losses so that spinel ferrites are used in many electronic and magnetic devices. 6
Ferrites have many importance in magnetic materials .These are-
1. High resistivity
2. Wide frequency range (10kHzto50MHz)
3. Low cost
4. Large selection material
5. Shape versatility
6. Economical assembly
7. Temperature and time stability
8. High Q/small package
In magnetic circuit ferrites are intended for both low level and power application because they have high frequency act of other circuit components continues to develop .They have advantageous arrangement of low cost ,high Q ,high stability and lowest volume so that these are finest core material choice for frequencies from 10KHz to %0MHz .In magnetic and mechanical considerations ferrites deal unmatched flexibility .7In recent years ,many consideration has been paid to Nano magnetic materials that response many magnetic properties .Ferrites have many promising characteristics .The important properties of High quality factor such as brilliant magnetic and electrical enactment ,low sensitivity to difference in the ambient temperature ,good sensibility with time ,satisfactory performance over the vital frequency band ,large number of controllable parameters i.e, their electrical magnetic properties can be organized by changing the relative percentage of numerous can constituents of cautions and they are cost effective. 8
1.3: APPLICATIONS OF FERRITE
Ferrite materials technology is in an on new aged now, in which the design engineers control the properties to enormous amount, to uniform the particular device .In recent year technology depend a lot to ferrites industry .Ferrites have great impact on ranging from the very ordinary radio sets to the complex and extensive hardware’s involved in computer .The first attraction of ferrites which is outstanding property is their very high electrical resistivity as compared to that of other metals .Eddy current losses are negligible at high frequency application ,in ferrites necessary materials telecommunication and in electronic industry where frequency range 103 to 1011 .Around 1950 ,new magnetic material was urgently need for telephone industry which was used as load coils of their long distance lines and magnetic in band pass filters .For these necessity ferrite introduce new requirement .Another important use of ferrite is in resonance circuit .For inductors ferrite core was used .As it control and minimize the various loss factor ,ferrite core become very efficient inductor which have high initial permeability and reduced physical size .Ferrite cores have high saturation induction and low hysteresis losses for these case core are used as power transformers . 8To control microwave transmission path ,frequency ,amplitude ,and phase microwave signals ,spinel ferrites are broadly used .To contribution in the production of ferrite ,perfect dielectric and magnetic property measurement at the operational frequency and temperature ranges are required for elevated improvement of theses metal . 9Magnetic materials have many possible application from information technology to biotechnology so that the structure of these materials are interesting field of study .9Magnetic materials have many possible application from information technology to biotechnology so that the structure of these materials significant field of research .10Now a days for development of the fabrication of multilayer chip inductors MLFCI as surface mount devices for miniaturized electronic products such as cellular phones ,digital diaries ,video camera recorders ,floppy drives, etc are greatly used of Ni-Cu-Zn spinel ferrites substituted rare earth iron .11To manufacture multilayer chip inductors thin sheets made of ferrite or special ceramics are used on which coil patterns are printed with metal paste .A spiral shape electrode pattern is designed by organizing these sheet in multiple layers .The coil was formed by using multilayer technique which is in a three dimensional space without the need to wind wire on a core and its facilitates miniaturization and mass production .At the time of flowing current through the coil magnetic flux is formed .The number of magnetic lines is known as inductance which is the intensity of the flux .The number of coil windings squared proportionally increased with the increased of inductance and proportionally to the cross section area. For higher magnetic permeability ferrites are used as a core results in higher inductance. The concentration of magnetic field lines are affected by higher magnetic permeability of core. As Ni-Cu-Zn ferrites have lower sintering temperature rather than other ferrites, these are potential material for the MLCIs. Different types of ferrites have been used In audio and visual tools such as liquid crystal TV set, head phone stereos, computer and telecommunications devices such as personal wireless communication system and automobile telephones.
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