Ferromagnets are materials that can become magnetized and retain their magnetic properties even after an external magnetic field is removed. This occurs because the magnetic moments of atoms in these materials align in the same direction, creating a strong overall magnetic field. Common examples of ferromagnetic materials include iron, cobalt, and nickel. The ability of ferromagnets to be magnetized is due to their atomic structure, which allows for a strong interaction between neighboring magnetic moments. This property makes ferromagnets useful in various applications, such as in electromagnets, magnetic storage devices, and transformers.