Domain Wall Energy Per Unit Area

The domain wall energy per unit area of.

Domain wall energy per unit area. Large so m z is uniform. 2jk s u bw a both exchange and anisotropy contribute to the energy penalty of a wall formation. The critical size below which magnetic particles are.

Domain formation in a saturated magnetic material is driven by the magnetostatic ms energy of the single domain state a. The precision is limited by sample inhomogeneity and experimental uncertainty not by inherent uncertainty in the technique. If the piece of the material were smaller than the size of the domain wall then this piece would consist of one single domain.

The magnetocrystalline anisotropy energy and the exchange energy both of which tend to be as low as possible so as to be in a more favorable energetic state. Exchange lengths are typically less than 10 nm. 18 can range from 5 nm to several hundred nanometers on going from hard to soft magnetic materials.

The exchange length l ex 2 a μ o m s 2 is the minimum distance over which the local moment direction can change to reduce magnetostatic energy. Calculation of the work exerted by the applied and demagnetizing magnetic fields in forcing the controlled increase of wall area yields the new measure of the domain wall energy per unit area. The increase of wall area has been observed by the bitter and faraday techniques.

About 200 oe between h and hz for a domain of radius r o 5pm. Domain wall energy gives rise to a force density which is. Calculation of the work exerted by the applied and demagnetizing fields in forcing this increase has yielded the new measure of the domain wall energy per unit area.

It is true for example for some nanoparticles. 90o closure domains eliminate ms energy but increase anisotropy energy in uniaxial material 16. The domain wall energy per unit area of erfeo 3 at 25 c has been measured to be 1 95 erg cm 2 5.