difference between soft & hard magnetic materials?
Hard Ferromagnetic Materials
In materials science, the coercivity, also called the coercive field, of a ferromagnetic material is the intensity of the applied magnetic field required to reduce the magnetization of that material to zero after the magnetization of the sample has been driven to saturation. Coercivity is usually measured in oersted or ampere/meter units and is denoted HC. Coercivity measures the resistance of a ferromagnetic material to becoming demagnetized. Coercivity can be measured using a B-H Analyzer. Materials with high coercivity are called hard ferromagnetic materials, and are used to make permanent magnets. Permanent magnets find application in electric motors, magnetic recording media (e.g. hard drives, floppy disks, or magnetic tape) and magnetic separation. A material with a low coercivity is said to be soft and may be used in microwave devices, magnetic shielding, transformers, or recording heads.
The materials that do not retain magnetism after being put in magnetic field are soft magnetic material. Those who retain are hard magnetic materials.
