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Difference Between Hard Iron and Soft Iron

Main Difference

The main difference between Hard iron and soft iron is that Hard Irons are the ferromagnetic substances that cannot be easily demagnetized once magnetized by an enforced change in the magnetic field. Whereas Soft Irons are the ferromagnetic substances that can be easily magnetized and re-magnetized with a small change in the magnetic field.

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Hard Iron vs. Soft Iron

Hard iron is the type of metal that, if magnetized, once cannot be demagnetized easily. It means if a hard iron is magnetized once it will not be easy to demagnetize it. However, soft irons can be re-magnetized with use of small change in electric force which differs it from hard iron due to this specific characteristic. Hard irons thus are known as hard magnetic material, whereas soft irons are called soft magnetic material. Hard irons have their applications as permanent magnets and commercially used wherever this specific property of these materials is required whereas, soft irons used as electromagnets. They have their uses as parts of electric motors and generators.

Hard irons have low susceptibility as they once magnetized, or their atoms are aligned does not reverse or change so easily. On the other hand, Soft irons have high susceptibility, and their alignment of atoms easily changes with the change in the electric field around it. Hard irons have high retentivity as they have higher retention for any changes made and are found nearly impossible to reverse the alignment. On the flip side, soft irons have a lower retention rate as their arrangement of atoms is just temporary, and due to this property, they can be easily re-magnetized and are used as soft magnets or electromagnets.

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Comparison Chart

Hard IronSoft Iron
The type of iron that if magnetized once cannot be demagnetized easilyThe type of iron that can be re-magnetized with use of change in electric force
Magnetic Property
These are hard magnetic materialsThese are soft magnetic materials
Re-magnetization
Once magnetized cannot be re-magnetized easily.Once magnetized can be re-magnetized easily.
Susceptibility
Hard irons are less susceptibleSoft irons are more susceptible
Retentivity
Hard irons have more retention of the effect of magnetizationSoft irons have less retention of the effect of magnetization
Alignment of Atoms
Alignment of atoms is nearly permanentAlignment of atoms is temporary

What is Hard Iron?

Ferromagnetic substances possess magnetization in the absence of an external magnetic field. Hard iron is the type of ferromagnetic material that, if magnetized, once cannot be demagnetized easily, which makes it a hard iron as the name indicates. This property differs from soft iron and has its uses for this distinctive characteristic. Hard ferromagnetic irons are also known as hard magnetic materials. Hard irons have their applications as permanent magnets and commercially used for their unique characteristics. Hard irons have low susceptibility towards changes in electric fields as once they are magnetized, or their atoms are aligned does not reverse or change so easily. It is also one of the properties of hard iron that differs from soft iron that has a higher retention rate of the alignment of atoms. As if once the atoms of a hard iron are aligned, it is not easy to amend or reverse it.

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Hard irons due to their specific characteristics have their use in industry in many areas. Steel is slow to magnetization, and it retains if once magnetized and is classified into hard iron. These magnetized steel bars are used as magnets in speakers and instruments.

What is Soft Iron?

Soft Iron is also a ferromagnetic substance, which means that it can act as a magnetic substance in the absence of an electric field. Soft iron is the type of ferromagnetic material. It possesses magnetization but can be re-magnetized with the use of small changes in electric force. This change in electric force is caused by the change in the alignment of atoms in the substance, which differs from hard iron due to this specific re-alignment characteristic. Soft irons are therefore known as soft magnetic materials.

Soft irons have a higher susceptibility to any change around them caused by the electric field, and their alignment of atoms easily changes with the changes in the field around it. It is also one of the properties of soft iron that has a lower retention rate of the alignment of atoms and its alignment of atoms changes whenever they are subjected to the electric field. It leads to the acquisition of a particular characteristic of its atoms being temporary aligned and are changed whenever they subjected to changes in electric field in its surrounding. Soft irons also have their use in industry in many areas due to specific characteristics. These are commonly used as electromagnets in motors and generators etc.

Key Differences

  1. Hard iron is the type of ferromagnetic substance that, if magnetized, once cannot be demagnetized easily. On the flip side, soft irons are the type of ferromagnetic iron that can be re-magnetized with the use of change in electric force.
  2. Hard irons are known as hard magnetic materials, whereas soft magnetic substances are known as soft magnetic materials.
  3. Hard irons are once magnetized cannot be re-magnetized easily; however, soft iron once magnetized can be re-magnetized easily.
  4. Hard irons are less susceptible to changes in the electric field. On the other hand, soft irons are more susceptible to changes in the electric field in its surrounding.
  5. Hard irons have more retention to the effect of magnetization once acquired. In contrast, soft irons have much less retention for the charge acquired and easily demagnetize as soon as the electric field in its surrounding changes.
  6. Hard irons align their atoms near to permanent. However, alignment in soft irons is very temporary.

Conclusion

Hard iron is the type of ferromagnetic substance that, if magnetized, once cannot be demagnetized easily. In contrast, soft irons are the type of ferromagnetic iron that can be demagnetized with the use of change in electric force.

Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss