Remanence English Name: residual magnetism; remanence residual magnetization referred to as.
Definition 1: the ferromagnetic material removal by magnetic field after magnetization, magnetization and the remaining on the ferromagnetic magnetization. Definition 2: ferromagnetic after magnetization, the magnetic induction intensity is still preserved in the external magnetic field disappeared under the circumstances.
Why magnetic polarization J arbitrary in the demagnetization curve of permanent magnetic materials on the measuring point value and the magnetic induction intensity B value must be less than Jr and Br values of remanence?
Permanent magnetic material in the closed state through the outer magnetic field magnetization to saturation, then cancel the external magnetic field, permanent magnetic material magnetic polarization of J and internal magnetic induction intensity B and will not disappear because of the disappearance of the H and the external magnetic field, and can maintain a certain size value, this value is called remanent polarization Jr the material and the residual magnetic induction intensity Br, referred to as the remanence.
The unit and the intensity of magnetization and the magnetic induction intensity of Jr and Br of the same unit of remanence. At the demagnetization curve of permanent magnetic materials, the magnetic field of H is 0, Jr=Br, magnetic field H is negative, J and B are not equal, then divided into J-H and B-H two curve. With the increase of the reverse magnetic field H, B from the maximum value of Br=Jr to 0, and finally to a negative value for modern permanent magnet materials, the law of change of B of the demagnetization curve often is the straight line; the regularity of J of the demagnetization curve is different: with the increase of the reverse magnetic field of H, the linear decrease of B value, due to the increased a small amount is always greater than or reverse magnetic field is equal to H minus B value, so a certain area in the J demagnetization curve can keep straight on the relatively flat, but the J value is less than Jr. |
