The physical principle behind magnetic levitation is that all diamagnetic objects magnetically polarize when immersed in a strong magnetic field. In the presence of a strong magnetic field gradient, parallel to the polarizing field, the diamagnetic sample experiences a magnetic force. Orienting this force opposite to the gravitational force can lead to no net force on the object; thus, levitation occurs
In most atomic elements, the structure of the atom is such that the electrons align in a random manner, rather like a bunch of basketballs bumping into one another as they float in a swimming pool. Because of this random alignment, the small magnetic fields cancel out one another. Two such self-canceling particles are referred to as paired electrons, and again, the analogy to bar magnets is an appropriate one: if one were to shake a bag containing an even number of bar magnets, they would all wind up in pairs, joined at opposing (north-south) poles.
There are, however, a very few elements in which the fields line up to create what is known as a net magnetic dipole, or a unity of direction—rather like a bunch of basketballs simultaneously thrown from in the same direction at the same time. These elements, among them iron, cobalt, and nickel, as well as various alloys or mixtures, are commonly known as magnetic metals or natural magnets.
Magnetism, along with electricity, belongs to a larger phenomenon, electromagnetism, or the force generated by the passage of an electric current through matter. When two electric charges are at rest, it appears to the observer that the force between them is merely electric. If the charges are in motion, however—and in this instance motion or rest is understood in relation to the observer—then it appears as though a different sort of force, known as magnetism, exists between them.
A permanent magnet is particular form of magnet that works at a permanent basis especially when it is compared to an electromagnet, which works like a magnet only when it is comes in contact with electric current. Difference between this two is also noticed in their production because the main component that is used to produce permanent magnets is Fe3O4 or magnetite and neodymium, which is a very potential magnetic and synthetic substance.
In 2005, Eric Stroud, the managing partner of Shark Defense, a New Jersey company that specializes in shark-repelling technologies, happened to be carrying a rare-earth magnet as he passed a tank full of sharks. The sharks fled, and Stroud took note. After further tests, Stroud and his colleagues found that sharks that came within 20 inches of rare-earth magnets similar to the one he had been carrying would consistently swim away.
Neodymium-iron-boron alloys are the basis for the most powerful permanent magnets, used in headphones, disk drives, and motors, and commonly known as neodymium magnets or rare earth magnets.
Today’s permanent magnets are made of alloys. Alloy materials include:
• Aluminum-Nickel-Cobalt (Alnico)
• Neodymium-Iron-Boron (Neodymium magnets or "super magnets" are a member of the rare earth category)
• Samarium-Cobalt (a member of the rare earth category)
• Strontium-Iron (Ferrite or Ceramic)
Magnetism is the force of attraction or repulsion between substances made of certain materials, such as iron, nickel, cobalt, and steel. The force of magnetism, simply put, is due to the motion of electric charges.
Natural magnetic material such as lodestone and magnetite, contain large amounts of iron. A story from the Arabian Nights mentions magnetic rocks. Ancient Chinese and Romans suspended a piece of magnetite rock by a thread and it lined up in a north-south direction, which helped them to navigate.
Magnets attract materials made from iron, nickel and cobalt and their alloys such as steel.