Final answer:
A ferromagnet near its critical point becomes highly sensitive to temperature, affecting its ability to be magnetized or retain its magnetic properties.
Step-by-step explanation:
A ferromagnet near its critical point is characterized by its magnetic properties becoming highly sensitive to temperature. When a ferromagnetic material is near its critical point, the thermal motion of the atoms disrupts and randomizes the orientation and size of the magnetic domains within the material. As a result, the material's ability to be magnetized or retain its magnetic properties is greatly affected by changes in temperature.
For example, above the Curie temperature, which is the well-defined temperature for ferromagnetic materials, they lose their ability to be magnetized. The Curie temperature for iron, a common ferromagnetic material, is 1,043 K (770 °C), which is well above room temperature.
Therefore, when a ferromagnet is close to its critical temperature, even small changes in temperature can have a significant impact on its magnetic properties. This sensitivity to temperature near the critical point is an important characteristic of ferromagnetic materials.