Magnetic materials are classified Based on application as :(a) Hard Magnetic Materials (b) Soft Magnetic Materials.
Difference between hard and soft magnetic materials are given below:
Difference between hard and soft magnetic materials are given below:
| # | Soft Magnetic Materials | Hard Magnetic Materials |
|---|---|---|
1
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Soft magnetic materials are those materials which can be easily magnetized and demagnetized.
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Hard magnetic materials when retaining their magnetism are difficult to demagnetize.
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2
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Loss their magnetism after the removal of the applied magnetic field
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Retain their magnetism even after the removal of the applied magnetic field
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3
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The domain wall movement is easy
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The movement of the domain wall is prevented.
|
4
|
Used for making temporary magnets
|
Used for making permanent magnets
|
5
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Low hysteresis and eddy current loss due to small hysteresis area
|
Large hysteresis and eddy current loss due to large hysteresis loop area
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6
|
Magnetic energy stored is less
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Magnetic energy stored is high
|
7
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Impurities decrease the strength of hard magnetic materials
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Impurities increase the strength of hard magnetic materials
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8
|
Susceptibility and permeability are high
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Susceptibility and permeability are low
|
9
|
Small coercivity and retentivity values
|
Large oercivity and retentivity values
|
10
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Hysteresis loop for a soft magnetic material is thin and long (steep curve).
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Hysteresis loop for a hard magnetic material is widen
|
11
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Examples : Soft iron, iron-Si alloys (3-4% Si), iron-cobalt-manganese alloys, Supermalloy (79% Ni-15.5% Fe-5% Mo-0.5% Mn), Permalloy (78.5% Ni-21.5% Fe etc.
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Examples: steel and special alloys such as Alcomax, Alnico, and Ticonal, which contain various amounts of aluminium, nickel, cobalt, and copper etc.
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12
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Applications: Soft magnetic materials are used in applications requiring frequent reversal of the direction of magnetization . Commonly used in electric bell, telegraphy, relay, transformer, dynamos, diaphragms of the telephones, switching circuits, magnetic amplifiers, magnetostrictive transducers, Signal transfer, Magnetic field screening etc.
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Applications: Soft magnetic materials are used in applications requiring permanent magnets. Commonly used in Loudspeaker, Small generators, Small motors, Sensors, Video tape, Audio tape, Ferrite core memory, Drum, Hard disc, Floppy disc, Quantum devices, Data storage unit, Bubble memory etc
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