Magnetic field:

(as defined by IEC) the components of an electromagnetic field are characterized by magnetic field intensity H and magnetic flux density B. (Chinese national standard definition) a magnetic field is a field characterized by the force exerted by the charged particles moving in the field. This force comes from the movement of the particles and their charges.

· hysteresis loop:

The closed relation curve of B and H is obtained by repeated magnetization of ferromagnet from forward to reverse and then forward to one week of technology saturation is called hysteresis loop.

· Remanence Br, UoMr or 4 PI Mr:

After the permanent magnet is magnetized to technical saturation and the external magnetic field is removed, the remaining Mr, UoMr or 4πMr or Br are called residual magnetization, residual intrinsic magnetic induction and residual magnetic induction, collectively called residual magnetization.

· Coercive force:

The reverse magnetic field strength required by Hcb and Hcj to reduce the B(magnetic induction strength) of permanent magnet magnetized to technology saturation to zero is called Hcj. Similarly, the reverse magnetic field strength required to reduce the intrinsic magnetic induction strength UoM or Mr To zero is called Hcj.

·Magnetic energy product:

(BH) Max demagnetization curve on any bit of B and H is the product of Bm, Hm and (BH) represents the magnet magnetic energy density in air gap space, that is the magnetostatic energy per unit volume of the air gap. The energy is equal to the magnet Bm and the product of Hm, so called magnetic energy product, the curve of magnetic energy product varies from B is called the magnetic energy curve, the product of Bd and Hd corresponding to a point has a value, which is called the magnetic energy product.

· Bending point Hk:

The magnetic field corresponding to the point Bi=0.9Br on the intrinsic demagnetization curve is usually referred to as the bending point magnetic field Hk. The larger the magnetic field Hk is, the better the squareness of the intrinsic demagnetization curve will be.

· Remanence temperature coefficient (Br) :

When the temperature changes within a certain range, the ratio of the percentage of the reversible change of the residual magnetic induction to the degree of temperature change is called the residual magnetic temperature coefficient.

· Coercivity temperature coefficient of magnetization strength (Hcj) :

When the temperature changes within a certain range, the ratio of the percentage of the reversible change of the magnetization coercivity to the degree of temperature change.

· Curie temperature:

Temperature at which Tc spontaneous magnetization disappears.