Permanent magnets

The materials used in making permanent magnets should have high retentivity, high coercivity & high permeability. High retentivity makes the magnet is strong and high coercivity ensures the magnetisation is not erased by stray magnetic fields, temperature fluctuations or minor mechanical damage.

Suitable materials for permanent magnets are steel, alnico, cobalt steel and ticonal. Steel is one-favoured choice. Coercivity of steel is very large as compared to that of the soft iron but its retentivity is slightly smaller retentivity. Permanent magnetism is used in making Electric meters, Loudspeekers etc.. e.g.   Steel, Alnico, Alcomax & Ticonal.