Which of the following materials are NOT considered ferromagnetic?

Ferromagnetic materials are those that can be magnetized and have high magnetic permeability, allowing them to become permanent magnets when exposed to a magnetic field. Iron, cobalt, and nickel are classic examples of ferromagnetic materials, all of which exhibit strong magnetic properties due to their atomic structure and the alignment of their magnetic moments.

Copper, on the other hand, is not a ferromagnetic material. It is classified as a diamagnetic material, which means it does not have the ability to retain magnetization in the absence of an external magnetic field. When exposed to a magnetic field, copper will produce a very weak, negative response, pushing the magnetic field away rather than amplifying it. This fundamental difference in how these materials react to magnetic fields indicates why copper stands apart from iron, cobalt, and nickel regarding ferromagnetism.

Understanding this distinction is key in the study of magnetic materials and their applications in various electrical and electronic devices.