page_title: Magnetic levitation
section_title: Diamagnetic levitation
hierarchical_section_title: Magnetic levitation / Methods / Diamagnetic levitation
caption_attribution_description: English: A small (~6mm) piece of pyrolytic graphite levitating over a permanent neodymium magnet array (5mm cubes on a piece of steel). Note that the poles of the magnets are aligned vertically and alternate (two with north facing up, and two with south facing up, diagonally)
context_page_description: Magnetic levitation or magnetic suspension is a method by which an object is suspended with no support other than magnetic fields. Magnetic force is used to counteract the effects of the gravitational acceleration and any other accelerations.
  The two primary issues involved in magnetic levitation are lifting forces: providing an upward force sufficient to counteract gravity, and stability: ensuring that the system does not spontaneously slide or flip into a configuration where the lift is neutralized.
  Magnetic levitation is used for maglev trains, contactless melting, magnetic bearings and for product display purposes.
context_section_description: Diamagnetism is the property of an object which causes it to create a magnetic field in opposition to an externally applied magnetic field, thus causing the material to be repelled by magnetic fields. Diamagnetic materials cause lines of magnetic flux to curve away from the material.  Specifically, an external magnetic field alters the orbital velocity of electrons around their nuclei, thus changing the magnetic dipole moment.
  According to Lenz's law, this opposes the external field. Diamagnets are materials with a magnetic permeability less than μ₀ (a relative permeability less than 1).  Consequently, diamagnetism is a form of magnetism that is only exhibited by a substance in the presence of an externally applied magnetic field. It is generally quite a weak effect in most materials, although superconductors exhibit a strong effect.
caption: Diamagnetic levitation of pyrolytic carbon
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