What is meant by magnetic areas?

Magnetic materials such as permanent magnets are divided into individual microscopic domains. The magnetic domain structure of a material is responsible for its magnetic properties as exhibited by metallic elements and alloys such as permanent magnets.
Each domain is a region that has a uniform direction of magnetization, but different domains can have different directions of magnetization. During the manufacturing process of magnetic materials, electromagnets align each domain to provide the greatest magnetic energy and impart anisotropy to the finished material.