Properties and uses of soft magnetic materials

Soft magnetic materials are those that can be magnetized and demagnetized easily.

Properties

• Low coercivity ($H_c$ < about 1000 A/m) and low retentivity.
• High permeability ($\mu_r$ of thousands to $10^5$).
• Narrow, tall hysteresis loop, so low hysteresis loss.
• High saturation flux density.
• High resistivity (in Si-steel and ferrites) for low eddy-current loss.
• Few impurities and defects, so domain walls move easily.

      B
      ^  __
      | / /   narrow loop
  ----+/-/----> H
     /-/ |

Uses