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When an iron air is introduced into a magnetic field it becomes magnetized, however, when the field is removed only a very small residual magnetic field due to the iron is left.
Hence iron is not a permanent magnetic material. A permanent magnet is when a material remains strongly magnetic after being excited by a magnetic field (magnetizing). A permanent magnetic material must also resist demagnetisation. In other worlds: under normal circumstances it should not lose its magnetism.
Permanent magnets are suitable for use in an impressive ranges of products: magnetic separators, meter, thermostats, toys, motors, household and medical equipment, speakers, etc.
Permanent magnets are available in various shapes, such as rings and blocks.