Georgia State University
Georgia State University: Hyper Physics: Ferromagnetism
This site from the Georgia State University provides a good overview of ferromagnetic materials, introducing concepts such as magnetic domains, hysteresis, the curie temperature, and magnetostriction.
Georgia State University
Georgia State University: Hyper Physics: Magnetic Properties of Solids
This site from the Georgia State University contains a good overview of some of the magnetic properties that are common to all materials, such as susceptibility and permeability, and then specific discussion of both diamagnetic and...
Wikimedia
Wikipedia: Diamagnetism
Wikipedia.com offers a good introduction to diamagnetism and diamagnetic materials, including discussion of how superconductors exhibit diamagnetic properties.
Other
University of Kiel: Paramagnetism
Although this is a technical description of paramagnetism, with many equations, it is still possible to glean conceptual information with a little bit of work.
Other
Sc Icentre: Magnets and Magnetism
Gives a simple description of the theory of magnetism and the properties of a magnet. Very good descriptions for beginning level.
Exploratorium
Exploratorium: Science Snacks: Magnetic Fruit: Push Me a Grape
An online activity which illustrates the magnetic property of diamagnetism associated with water. Contains a simple procedure and then a good explanation of the magnetic interactions that were displayed by the grapes.
Georgia State University
Georgia State University: Hyper Physics: Diamagnetism
This site from the Georgia State University provides a brief introduction to diamagnetism, explaining how Lenz's law accounts for diamagnetic behavior in all materials.
Wikimedia
Wikipedia: Paramagnetism
This Wikipedia site is an introduction to paramagnetism and paramagnetic materials.
Wikimedia
Wikipedia: Ferromagnetism
This site from Wikipedia provides a wonderful in-depth explanation of ferromagnetism, covering the atomic behavior which is responsible for ferromagnetic properties. Also introduces the concepts of magnetic domains and the Curie...
Integrated Publishing
Integrated Publishing: Theories of Magnetism
This site from Integrated Publishing provides three different examples of theories of magnetism.
Georgia State University
Georgia State University: Hyper Physics: Paramagnetism
This site from the Georgia State University provides a brief introduction to paramagnetism, explaining how paramagnetic materials exhibit magnetization proportional to an applied magnetic field according to Curie's law.