CHEMISTRY MODULE No.31 : Magnetic Properties of Transition

Web links

 http://en.wikipedia.org/wiki/Magnetism  http://wwwchem.uwimona.edu.jm/courses/magnetism.html  https://www.boundless.com/chemistry/textbooks/boundless-chemistry-textbook/transition- metals-22/bonding-in-coordination-compounds-crystal-field-theory-160/magnetic-properties- 616-6882/  http://en.wikipedia.org/wiki/Transition_metal  http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Crystal_Field_Theory/Crystal_Field_Theo ry/Magnetic_Properties_of_Coordination_Complexes

Suggested Readings Miessler, G. L.; Tarr, D. A. (2003). Inorganic Chemistry (3rd ed.). Pearson Prentice Hall. ISBN 0-13-035471-6

Drago, R. S.Physical Methods In Chemistry. W.B. Saunders Company. ISBN 0721631843 (ISBN13: 9780721631844)

Huheey, J. E.; Keiter, E.A. ; Keiter, R. L. ; Medhi O. K. Inorganic Chemistry: Principles of Structure and Reactivity.Pearson Education India, 2006 - Chemistry, Inorganic

CHEMISTRY PAPER No.: 7; Inorganic Chemistry-II (Metal-Ligand Bonding, Electronic Spectra and Magnetic Properties of Transition Metal Complexes) MODULE No.31 : Magnetic properties of transition metal ions

Carlin, R. L. Magnetochemistry. SPRINGER VERLAG GMBH. ISBN 10: 3642707351 / ISBN 13: 9783642707353

SELWOOD, P. W. MAGNETOCHEMISIRY. Swinburne Press. ISBN 1443724890.

Earnshaw, A. Introduction to Magnetochemistry Academic Press. ISBN 10: 1483255239 / ISBN 13: 9781483255231

Lacheisserie É, D. T. De; Gignoux, D., Schlenker, M. Magnetism

Time-Lines  Timeline Image Description s 1600

Dr. William Gilbert published the first systematic experiments on magnetism in "De Magnete". Source: http://en.wikipedia.org/wiki/William_Gilbert_(astronomer)

1777 Charles-Augustin de Coulomb showed that the magnetic repulsion or attraction between magnetic poles varies inversely with the square of the http://en.wikipedia.org/wiki/Charles-Augustin_de_Coulomb distance r. 1819 Hans Christian Ørsted accidentally made the connection between magnetism and electricity discovering that a current carrying http://en.wikipedia.org/wiki/Hans_Christian_%C3%98rsted wire deflected a compass needle. 1820 André-Marie Ampère discovered that the magnetic field circulating in a closed-path was related to the current flowing

through the http://en.wikipedia.org/wiki/Andr%C3%A9-Marie_Amp%C3%A8re perimeter of the path.

1820

http://en.wikipedia.org/wiki/Carl_Friedrich_Gauss

Carl Friedrich Gauss; Jean- Baptiste Biot and Félix Savart, came up with the Biot– Savart law giving an equation for the magnetic field from a current- http://en.wikipedia.org/wiki/Jean-Baptiste_Biot carrying wire.

http://www.appl-lachaise.net/appl/article.php3?id_article=682 1825

William Sturgeon invented the electromagnet.

http://en.wikipedia.org/wiki/William_Sturgeon

1831 Michael Faraday, found that a time- varying magnetic flux through a loop of wire induced a voltage, and others finding further links between http://en.wikipedia.org/wiki/File:M_Faraday_Th_Phillips_oil_1842.j magnetism and pg electricity. 1831 Joseph Henry discovered electromagnetic induction independently of and at about the same time as Michael Faraday. In physics, and electronics, the http://en.wikipedia.org/wiki/Joseph_Henry henry (symbol H) is the SI derived unit of inductance. It is named after Joseph Henry.

1861 James Clerk Maxwell, a Scottish mathematical physicist, proposed a set of mathematical equations describing physical explanation of http://en.wikipedia.org/wiki/James_Clerk_Maxwell electricity and magnetism. 1880

E. Warburg produced the first hysteresis loop for iron.

http://en.wikipedia.org/wiki/Emil_Warburg CHEMISTRY PAPER No.: 7; Inorganic Chemistry-II (Metal-Ligand Bonding, Electronic Spectra and Magnetic Properties of Transition Metal Complexes) MODULE No.31 : Magnetic properties of transition metal ions

1885

Oliver Heaviside coined the term Magnetic permeability.

http://en.wikipedia.org/wiki/Oliver_Heaviside 1895

Pierre Curie proposed Curie law.

http://en.wikipedia.org/wiki/Pierre_Curie 1905

Paul Langevin explained the theory of diamagnetism and paramagnetism.

http://en.wikipedia.org/wiki/Paul_Langevin 1906

Pierre-Ernest Weiss proposed ferromagnetic theory.

http://theor.jinr.ru/~kuzemsky/pwbio.html

1920's John Hasbrouck Van Vleck developed the physics of magnetism with theories involving electron spins and exchange

interactions; the http://en.wikipedia.org/wiki/John_Hasbrouck_Van_Vleck beginnings of quantum mechanics.

In 1932, He wrote a book on “Theory of Electric and Magnetic Susceptibilities”. 1932 Louis Eugène Félix Néel suggested a new form of magnetic behavior called antiferromagnetism . In 1947, Néel discovered ferrimagnetism in http://en.wikipedia.org/wiki/Louis_N%C3%A9el some materials.

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Did You Know?

1. Ferromanganese is a ferroalloy with high percentage of manganese. Ferromanganese is made by heating a mixture of the oxides MnO2 and Fe2O3, with carbon, usually as coal and coke, in either a blast furnace or a submerged arc furnace. The oxides undergo carbothermal reduction in the furnaces, producing the ferromanganese. Ferromanganese is used as a deoxidizer for steel. Henry Bessemer invented the use of ferromanganese as a method of introducing manganese in controlled proportions during the production of steel. Spiegeleisen is a ferromanganese alloy containing approximately 15% manganese and small quantities of carbon and silicon.

2. Permanent magnets

Permanent magnets are hard ferromagnetic materials. These are usually ferroalloys such as alnico and ferrite. These materials are subjected to special processing in a powerful magnetic field during manufacture, to align their internal microcrystalline structure, making them very hard to demagnetize. Some examples of ferromagnets are,

1. Alnico is a iron alloy with some percentage of aluminium (Al), nickel (Ni) and cobalt (Co). Hence it is called al-ni-co. Alnico can also contain copper, and sometimes titanium. Alnico alloys are ferromagnetic, with a high coercivity and are used to make permanent magnets. Before 1970s, when there were no rare earth magnets, Alnico were the strongest type of magnet. The composition of alnico alloys is typically 6–12% Al, 13–26% Ni, 0–42% Co, up to 6% Cu, up to 9% Ti, and the balance is Fe.

In 1956, Alnico magnets led to a generation of compact permanent magnet motors and loudspeakers. Alnico magnets are also used in a magnetron tube in an early microwave oven.

2. Samarium–cobalt (SmCo) magnet, is an alloy of samarium and cobalt. Samarium–cobalt (SmCo) magnets are strong permanent magnet with a high coercivity. It is developed in the early 1970s. They are available in two "series", namely Series 1:5 and Series 2:17. Samarium Cobalt was used in Guitars and Basses as Noiseless Pickups. Samarium Cobalt were also used in some headphones as "Super Magnet" transducers. SmCo is also used in high-end electric motors used for competitive classes in slotcar racing, turbomachinery, traveling-wave tube field magnets etc.