Which of the following materials would you expect to have domains?

Ferromagnetic materials are characterized by the presence of magnetic domains, which are regions within the material where the magnetic moments of atoms are aligned in the same direction. This alignment results from the interactions between neighboring atoms' magnetic moments, leading to a strong overall magnetic effect. When these domains are aligned, the material exhibits a net magnetic field, which is why ferromagnetic materials can be permanently magnetized.

In contrast, diamagnetic materials do not have any magnetic domains; they exhibit a very weak, negative magnetic response when an external magnetic field is applied due to the absence of unpaired electrons. Paramagnetic materials also lack permanent domains; they contain unpaired electrons that align with an external magnetic field but do not retain this alignment in the absence of the field. Superconductors, while exhibiting unique electromagnetic properties, do not have magnetic domains as understood in ferromagnetic materials. Instead, they expel magnetic fields entirely due to the Meissner effect when cooled below their critical temperature.

Thus, the presence of domains is a defining feature of ferromagnetic materials, distinguishing them from the other types listed.