B−H curve drawn for only ferromagnetic material. Retentivity of soft iron is more than steel but coercivity of steel is more. retentivity-the ability of a substance to retain or resist magnetization, frequently measured as the strength of the magnetic field that remains in a sample after removal of an inducing field. coercivity-the resistance of a magnetic material to changes in magnetization, equivalent to the field intensity necessary to demagnetize the fully magnetized material.