In case of polycrystalline solids, the various crystals in a polycrystals are randomly oriented, so that properties are same in all directions. However if specific treatment such as cold rolling is given to certain polycrystalline substances, then magnetic properties become different in different directions. This anisotropy produced in the material is called induced anisotropy.

This property is of practical importance.

Example: thin films of Ni-Fe alloy deposited on to a substrate by evaporation in vacuum with magnetic field applied in the plane of the substrate show spontaneous magnetisation in the direction of the applied field. These magnetic films are used as storage devices in computers.

Reference: This article is referred from my book “electrical engineering materials” having ISBN 978-81-272-5069-0