How does a permanent magnet work? :: essays research papers

more or less genuines lead a feature cognize as ferromagnetism. The prefix "ferro" refers to Iron, which is cardinal such material. Ferromagnetic materials have the ability to "remember" the magnetic area they have been subjected to. An atom consists of a number of negatively charged electrons, orbiting some a positively charged nucleus. These electrons also possess a measure known as twisting, which is roughly analogous to a spinning top. The combine of orbital and spin motions is called the angular whim of the electron. Angular momentum is perhaps most easily understood in the case of the Earth The acres spins about a central axis, which means it at has an angular momentum around that axis. The planets also have an angular momentum as they drift about the sun. Now, the angular momentum of an electron is a vector quantity, sum it has direction. The motion of the electron produces a current, which in turn generates a midget magnetic range in the dire ction given by the angular momentum. Thus an atom can behave like a dipole, meaning "two poles". The direction of the orbital and spin angular momentum of the electron determine the direction of the magnetic field for the electron and the entire atom, and so giving it "north" and "south" poles. Different atoms have different arrangements of electrons into their orbits, and therefrom have different angular momenta and dipolar properties. A ferromagnetic material is composed of many microscopic magnets known as empyreans. Each domain is a region of the magnet, consisting of numerous atomic dipoles, all pointing in the equal direction. A strong magnetic field go forth align the domains of a ferromagnet, or in other words, magnetize it. Once the magnetic field is removed, the domains will remain aligned, resulting in a permanent magnet. This effect is known as hysteresis. Few materials are actually ferromagnetic however, all substances have a diamagnetic na ture. Diamagnetism means that the molecules inside a substance will align themselves to an foreign magnetic field. The external magnetic field induces currents within the material, which in turn result in an internal magnetic field in the opposite direction. This effect is usually quite small and disappears when the external magnetic field is removed. Some materials are paramagnetic. This is the case when the orbital and spin motions of the electrons in a material do not fully scrape each other, so that the individual atoms act like magnetic dipoles.