What objects do magnets stick to?

Hint: We start by stating the classification of types of materials based on their magnetic properties. Then as we define these materials, we give some examples as well. We then see what is required for a material to stick to a magnet. We observe the following types of materials and see which type of material possesses those requirements. Thus, we get the solution required.

Complete answer:
Let us start with the classification of materials based on their magnetic properties. Materials are classified into three bases on their magnetic properties. They are as follows:
1. Ferromagnetic materials: Ferromagnetism is a mechanism by which certain materials form permanent magnets, or are attracted to magnets. The elements exhibiting this property are called ferromagnetic materials. Some examples are iron, nickel and cobalt.
2. Ferrimagnetic materials: A ferrimagnetic material is one that has numerous atoms with opposing magnetic moments. Magnetite is one of the examples of a ferrimagnetic material. The magnetic moments are unequal and hence spontaneous magnetization remains.
3. Antiferromagnetic: Antiferromagnetism is the mechanism where the adjacent atoms behave as small magnets align themselves at low temperature atmospheres in parallel arrangements. Examples include hematite and metals such as chromium.
Materials with permanent dipole moments stick to a magnet.
In conclusion, ferromagnetic materials stick to a magnet.

Note: All three of these materials are magnetic materials but only ferromagnetic materials have permanent dipole moments. The other two materials are magnetic but only under specific conditions. For instance, antiferromagnetic materials have aligned dipoles and exhibit magnetic properties only at low temperatures.