× Home MCQ Videos Basic Electrical Circuit Theories Electrical Laws Materials Batteries Illumination Generation Transmission Distribution Switchgear Protection Measurement Control System Utilities Safety Transformer Motor Generator Electrical Drives Electronics Devices Power Electronics Digital Electronics

Magnetostriction

The meaning of striction is the state of being constricted. When a magnetic field is given to a magnetic material, it experiences an alteration in shape or size or length or dimension. This property of some magnetic materials is known as magnetostriction. This change of dimension of magnetic materials during magnetization may continue till the magnetic saturation of the material is attained. The change in length of a ferromagnetic iron rod when magnetized was first discovered by James Joule in 1842. This is the Joules effect. Ferromagnetic material and ferri-magnetic material exhibit this effect. Manetostriction can be calculated by the magnetostriction coefficient or Joule’s magnetostriction coefficient. It is the fractional variation in length as the magnetization raises from 0 to saturation value. It is denoted by λ. If the length of a ferromagnetic rod is L and after magnetizing it from zeros to saturation level the change in length is δL.
Then the ratio of δL to L is Joule’s magnetostriction coefficient (λ). λ = δL / L. There is a loss in energy due to friction in magnetic material cores.

This effect is the reason of humming sound that we hear in transformer. Next, we can go through some of the effects used in magnetostriction. They are

The structure of the ferromagnetic substances is alienated into domains. Each domain is a region of identical magnetic polarization. When a peripheral magnetic field is applied, the borders linking the domains move and domains revolve. As a result, there will be change in the dimension of the material. This effect is the outcome of magneto crystalline anisotropy. Thus, a strain is induced in the material.

This is because dissimilar crystal directions are related with dissimilar length. Matteucci effect and Wiedemann effect are linked with magnetostriction. They are explained above. Villari effect is contrary of magnetostriction effect.

Magnetostriction Materials

This effect is mostly seen in the magnetic materials such as iron, nickel, cobalt, iron-aluminium alloy and some other alloys like Terfenol-D, Galfenol, Metgla etc. They are mainly used in actuators and some motors.



JJOSH commented on 21/05/2018
Nice explanation
Comments

Related Articles Electrical Engineering MaterialsAtomAtomic Energy LevelsClassification MaterialsClassification of Electrical MaterialsElectron Configuration of AtomProperties of MaterialsMechanical Properties MaterialsRutherford Atomic ModelBohrs Atomic Model Chemical Properties of MaterialsEnergy Bands in CrystalsProperties of MaterialsFermi Dirac Distribution FunctionMagnetic Properties MaterialsThermionic EmissionSelection of MaterialsExistence of Properties in MaterialsQuantum NumbersConducting MaterialHigh Resistive MaterialsFactors Effecting ResistivityMaterials Used for Heating ElementsMaterials Used for Precious WorksMaterials Used for Transmission Line ConductorStranded ConductorsElectrical ConductorMaterials used for RheostatsMaterials for Lamp FilamentsClassification Conducting MaterialsApplications of Carbon MaterialsElectrical Contact MaterialsBimetalsIonic PolarizationPiezoelectricityDielectric MaterialsMechanism of PolarizationDielectric MaterialOrientational PolarizationElectric Arc FurnaceThermal Conductivity of MetalsFree Electron TheoryMagnetostrictionAntiferroelectricityFerroelectric MaterialsElectronic PolarizationFerromagnetic MaterialsMore Related Articles AtomSuperconductorNew Articles Natural Gas Power GeneratorsHow to Choose the Best Theater Lighting Equipment?How to Make an Electric Water Pump?Voltage RegulatorsTuned Collector Oscillator Articles Categories MCQ Contact Us Basic Electrical Circuit Theories Electrical Laws Materials Batteries Illumination Generation Transmission Distribution Switchgear Protection Measurement Control System Utilities Safety Transformer Motor Generator Electrical Drives Electronics Devices Power Electronics Digital Electronics Videos