Villari effect

Magnetostriction:

When a magnetic material is magnetize, changes in dimensions is called magnetostriction. It is caused by rotation of domain of ferro magnetic material under the influence of the applied magnetic field. Humming noise in the transformer, is the effect of magnetostriction,

Villari Effect:

• The change in magnetization can be produced by the effect of mechanical deformation (Streching, bending, twisting..) on the ferromagnetic material is called villari effect.
• The operating principle is based on the inverse magnetostrictive effect, which is also called the Villari effect.
• Change in magnetization can be produced by applying stress on the material.

• It is caused by change of disorder in domain of ferro magnetic material under the influence of the applied magnetic field.
• The longitudinal deformation leads to change in magnetic permeability of the material in the direction of the applied stress.
• Change of magnetization takes place by the effect of stress applied on the material.