In magnet This magnetic field is invisible but is responsible for the most notable property of a magnet, a force that pulls on other ferromagnetic materials, such as iron, and attracts or repels other magnets. It attracts ferrous objects like pieces of iron, steel, nickel and cobalt.The space surrounding a magnet, in which magnetic force is exerted, is called a magnetic field. If a bar magnet is placed in such a field, it will experience magnetic forces. However, the field will continue to exist even if the magnet is removed. The direction of magnetic field at a point is the direction of the resultant force acting on a hypothetical North Pole placed at that point.
Magnetism is property of materials that respond at an atomic or subatomic level to an applied magnetic field. For example, the most well known form of magnetism is ferromagnetism such that some ferromagnetic materials produce their own persistent magnetic field. However, all materials are influenced to a greater or lesser degree by the presence of a magnetic field. Some are attracted to a magnetic field (paramagnetism), others are repulsed by a magnetic field (diamagnetism), others have a much more complex relationship with an applied magnetic field. Substances that are negligibly affected by magnetic fields are known as non-magnetic substances. They include copper, aluminium, gases, and plastic.
Non-magnetic substances have little reaction to magnetic fields. They may be composed of molecules where electrons spinning one way are always balanced by electrons spinning the other, or their spins may simply interact only weakly. Most materials we encounter have no obvious magnetic properties – they are said to be non-magnetic. In these materials, the magnetic fields of the individual atoms are randomly aligned and thus tend to cancel out.