Ferromagnetic materials are substances that can be magnetized and retain their magnetic properties even after an external magnetic field is removed. Common examples include iron, nickel, and cobalt. These materials have regions called magnetic domains, where the magnetic moments of atoms align in the same direction, contributing to their overall magnetism. When exposed to a magnetic field, the domains in ferromagnetic materials can become aligned, enhancing their magnetic strength. This property makes them essential in various applications, such as electric motors, transformers, and magnetic storage devices. Their ability to be magnetized and demagnetized is crucial for many technological advancements.