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Web links

 http://en.wikipedia.org/wiki/Magnetism  http://electrons.wikidot.com/magnetism-iron-oxide-magnetite  http://encyclopedia2.thefreedictionary.com/Lanthanides  http://en.wikipedia.org/wiki/Lanthanide#Magnetic_and_spectroscopic  http://www.radiochemistry.org/periodictable/la_series/L8.html

Suggested Readings Miessler, G. L.; Tarr, D. A. (2003). Inorganic (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. : Principles of Structure and Reactivity.Pearson Education India, 2006 - Chemistry, Inorganic Carlin, R. L. Magnetochemistry. SPRINGER VERLAG GMBH. ISBN 10: 3642707351 / ISBN 13: 9783642707353

CHEMISTRY PAPER No.: 7; Inorganic Chemistry-II (Metal-Ligand Bonding, Electronic Spectra and Magnetic Properties of Complexes) MODULE No. 30: Van-Vleck equation

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

CHEMISTRY PAPER No.: 7; Inorganic Chemistry-II (Metal-Ligand Bonding, Electronic Spectra and Magnetic Properties of Transition Metal Complexes) MODULE No. 30: Van-Vleck equation

Time-Lines  Timelines Image Description

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 distance r.

http://en.wikipedia.org/wiki/Charles- Augustin_de_Coulomb 1819

Hans Christian Ørsted accidentally made the connection between magnetism and electricity discovering that a current carrying wire deflected a compass needle.

http://en.wikipedia.org/wiki/Hans_Chr istian_%C3%98rsted

CHEMISTRY PAPER No.: 7; Inorganic Chemistry-II (Metal-Ligand Bonding, Electronic Spectra and Magnetic Properties of Transition Metal Complexes) MODULE No. 30: Van-Vleck equation

1820

André-Marie Ampère discovered that the circulating in a closed-path was related to the current flowing through the perimeter of the path.

http://en.wikipedia.org/wiki/Andr%C3 %A9-Marie_Amp%C3%A8re

1820

http://en.wikipedia.org/wiki/Carl_Frie drich_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-carrying wire. http://en.wikipedia.org/wiki/Jean- Baptiste_Biot

http://www.appl- lachaise.net/appl/article.php3?id_articl e=682

CHEMISTRY PAPER No.: 7; Inorganic Chemistry-II (Metal-Ligand Bonding, Electronic Spectra and Magnetic Properties of Transition Metal Complexes) MODULE No. 30: Van-Vleck equation

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 magnetism and electricity. http://en.wikipedia.org/wiki/File:M_Fa raday_Th_Phillips_oil_1842.jpg 1831 Joseph Henry discovered electromagnetic induction independently of and at about the same time as Michael Faraday. In , and electronics, the henry (symbol H) is the SI derived unit of inductance. It is named after Joseph Henry.

http://en.wikipedia.org/wiki/Joseph_H enry 1861

James Clerk Maxwell, a Scottish mathematical , proposed a set of mathematical equations describing physical explanation of electricity and magnetism.

http://en.wikipedia.org/wiki/James_Cl erk_Maxwell

CHEMISTRY PAPER No.: 7; Inorganic Chemistry-II (Metal-Ligand Bonding, Electronic Spectra and Magnetic Properties of Transition Metal Complexes) MODULE No. 30: Van-Vleck equation

1880

E. Warburg produced the first hysteresis loop for iron.

http://en.wikipedia.org/wiki/Emil_War burg 1885

Oliver Heaviside coined the term Magnetic permeability.

http://en.wikipedia.org/wiki/Oliver_He aviside 1895

Pierre Curie proposed Curie law.

http://en.wikipedia.org/wiki/Pierre_Cu rie 1905

Paul Langevin explained the theory of and .

http://en.wikipedia.org/wiki/Paul_Lan gevin 1906

Pierre-Ernest Weiss proposed ferromagnetic theory.

CHEMISTRY PAPER No.: 7; Inorganic Chemistry-II (Metal-Ligand Bonding, Electronic Spectra and Magnetic Properties of Transition Metal Complexes) MODULE No. 30: Van-Vleck equation

http://theor.jinr.ru/~kuzemsky/pwbio.h tml

1920's John Hasbrouck Van Vleck developed the physics of magnetism with theories involving spins and exchange interactions; the beginnings of .

In 1932, He wrote a book on “Theory of Electric and Magnetic http://en.wikipedia.org/wiki/John_Has Susceptibilities”. brouck_Van_Vleck 1932

Louis Eugène Félix Néel suggested a new form of magnetic behavior called . In 1947, Néel discovered in some materials.

http://en.wikipedia.org/wiki/Louis_N %C3%A9el

Biographic sketch

Description Image John Hasbrouck Van Vleck, an American Physicist and Mathematician He was cowinner of the 1977 for his contributions in Physics. He got Nobel Prize for his fundamental theoretical investigations of the electronic structure of magnetic and disordered systems. His father, was a mathematician, and grandfather, John Monroe Van Vleck, was astronomer. J.H. Van Vleck established the fundamentals of the quantum mechanical theory of magnetism and the PAPER No.: 7; Inorganic Chemistry-II (Metal-Ligand Bonding, Electronic Spectra and Magnetic Properties of Transition Metal Complexes) MODULE No. 30: Van-Vleck equation

field theory. He is regarded as the Father of Modern Magnetism. During Second World War, he worked on at the Radiation Lab in Massachusetts Institute of Technology. He showed that at about 1.25 cm water and 0.5 cm wavelength molecules in the atmosphere would lead to troublesome absorption. This was very useful information for military radar systems and for the new science of radioastronomy.

Born 13 March 1899 Middletown, Connecticut

Died 27 October 1980 Cambridge, Massachusetts

Source: http://www.nobelprize.org/nobel_prizes/physics/laureates/1977/vleck-bio.html

Did You Know?

Rare Earth Garnets are complex oxides having the general formula A3B2X3O12. For rare earth garnets, A site is usually distorted cubic environment, however, B/X sites are octahedral & tetrahedral sites. The unit cell of Garnet contains approximately 128 . Rare Earth Garnets show interesting magnetic properties. For example,

1. Yttrium iron garnet (YIG): Chemical composition Y3Fe2(FeO4)3, or Y3Fe5O12. It is a ferrimagnetic material with a of 550 K. YIG is used in microwave, optical, and magneto-optical applications.

2. Gallium Garnet (GGG): Chemical composition Gd3Ga5O12. It is a synthetic crystalline material of the garnet group, with good mechanical, thermal, and optical properties. It is used in fabrication of various optical components and as substrate material for magneto–optical films.

3. Terbium gallium garnet (TGG): Chemical composition Tb3Ga5O12.This is a Faraday rotator material with excellent transparency properties and is very resistant to laser damage. TGG can be used in optical isolators for laser systems, in optical circulators for fiber optic systems, in optical modulators, and in current and magnetic field sensors.

CHEMISTRY PAPER No.: 7; Inorganic Chemistry-II (Metal-Ligand Bonding, Electronic Spectra and Magnetic Properties of Transition Metal Complexes) MODULE No. 30: Van-Vleck equation

CHEMISTRY PAPER No.: 7; Inorganic Chemistry-II (Metal-Ligand Bonding, Electronic Spectra and Magnetic Properties of Transition Metal Complexes) MODULE No. 30: Van-Vleck equation