Understanding Magnetostrictive Materials

Magnetostriction is mostly found in

• magnetic transition materials like iron, cobalt, nickel and
• the rare earth materials like lanthanum and terbium.
  
  

The grains of these materials consist of numerous small randomly oriented domains which can rotate and align under the influence of an external magnetic field. The magnetic orientation or alignment causes internal strain in the material which is known as magnetostriction [Figure 12.1].

Figure 12.1: Magnetostriction in a ferromagnetic material (a) paramagnetic state above Tc; (b) after it has cooled through Tc; and (c) after it has been brought to saturation by
a field H. [Dapino et al, 1999]