Category Archives: Magnetic Materials

Ohm’s law and its derivation

MOBILITY OF THE ELECTRON AND CURRENT Mobility of electron (ue) is defined as the drift velocity of electron per unit electric field applied. ue= drift velocity/electric field= Vd/E Thus                                 Vd=ueE The  SI unit of mobility is m2s-1V-1 or ms-1N-1C … Continue reading

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RELATION BETWEEN CURRENT AND DRIFT VELOCITY

Let l is the length of the conductor and A uniforms area of cross-section. Therefore, the volume of the conductor = Al If n is the number of free electrons per unit volume of the conductor, then the total number … Continue reading

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Coercivity

Coercivity is defined as the value of the magnetising field at which the intensity of magnetisation becomes zero. It is also known as coercive field. Hence, the coercivity of a material is a measure of the strength of the reverse … Continue reading

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Retentivity

The magnetism remaining in the magnetic material, even when the magnetising field is reduced to zero is called residual magnetism. The power of retaining this magnetism is called the retentivity or remanence. Therefore, the retentivity is also defined as the … Continue reading

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Soft magnetic materials

Soft magnetic materials have low retentivity and low coercivity. These are those materials which have high initial permeability, low hysterisis loss and large magnetic induction. These materials can be easily magnetised and demagnetised. Therefore, these are known as soft magnetic … Continue reading

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Ferrites

Ferrimagnetic materials commonly known as ferrites, can be generally represented by chemical formula XOFe2O3, where X stands for Mn, Co, Ni, Cu, Mg, Zn, Cd etc. If X is Fe, then compound is Fe3O4. X-ray crystallography proves that ferrites are … Continue reading

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Applications of ferrites

Ferrites have following applications: Ferrites have importance in engineering and technology because they possess spontaneous magnetic moment below the Curie temperature just as iron, cobalt, nickel. Due to vey low eddy current losses, ferrites are used as a core of … Continue reading

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Hard magnetic materials

Hard magnetic materials are those which have high coercivity, high retentivity and low loss in magnetisation due to mechanical treatment and no effect of temperature. These materials are called hard because these are difficult to magnetise and demagnetise. The higher … Continue reading

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Induced anisotropy

In case of polycrystalline solids, the various crystals in a polycrystals are randomly oriented, so that properties are same in all directions. However if specific treatment such as cold rolling is given to certain polycrystalline substances, then magnetic properties become … Continue reading

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Magnetic Anisotropy

Magnetic anisotropy is that property due to which ferromagnets tend to magnetize along certain crystallographic axes, called directions of easy magnetization. Example: In certain single crystals such as iron. The magnetic properties depend upon the direction in which these are … Continue reading

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