Magnetism

Based on paired or unpaired electrons.

Magnestic rock were discovered by the ancient Greeks to attract iron.

Robert Norman - Made compasses and discovered the needle not only pointed north but also dipped down towards the earth. Performed first experiments with needles and floating corks to suggest the existence of magnetic fields. William Gilbert - cataloged the properties of magnets establishing north and south poles. Proposed the poles of the earth and the compass aligns along field lines. Michael Faraday - iron filings around magnet Benjamin Franklin - suggested charged objects is related the amount of electric fluid .i.e modern electrons. Excess electrons gives negative charge. Charles Coulomb - established the law between two charges. F = k * (q_1 * q_2)/d^2. The electrostatics force is either attracive or negative. The physical origins of electric charge are stilll unknown.
 * Historic Pioneers of Electromagnetis**

How to get unpaired electrons?

Molecular Orbital Theory
Crystal Field Theory: explains spins in transition metals somprising d-orbitals
 * [/image of d-orbitals]
 * d^n configuration
 * high/low spin
 * geometry: octahedral, tetrahedral, square planar

Magnetic Properties

 * paramagnetism: unpaired, high spin
 * diamagnetism: paired electrons, low spin
 * ferromagnetism:

Energy Hysteresis loops and area in loops

Applications
 * Spintronics