A ferromagnetic material becomes strongly magnetic when its domains are:

1. Domains are themselves magnets, so their arrangement matters. 2. Ferromagnetic materials contain magnetic domains that are themselves magnets. 3. The regions within the material called domains act like small bar magnets. 4. Randomly oriented domains cancel one another out. 5. Aligning them makes their fields add, so the material is strongly magnetic. _Source: OpenStax College Physics for AP Courses 2e (CC BY 4.0), Ch 22 'Magnetism', sections 22.1-22.11_