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MAGNETIC MATERIALS. Origin of Magnetism Types of Magnetism Hard and Soft Magnets. Magnetic Materials – Fundamentals and Device Applications Nicola Spaldin Cambridge University Press, Cambridge (2003). BASICS. Material in a Magnetic Field.
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MAGNETIC MATERIALS • Origin of Magnetism • Types of Magnetism • Hard and Soft Magnets Magnetic Materials – Fundamentals and Device Applications Nicola Spaldin Cambridge University Press, Cambridge (2003)
Material in a Magnetic Field • The response of a material to a Magnetic Field H is called Magnetic Induction B • The relationship between B and H is a property of the material • In some materials and in free spaceB is a linear function of H but in general it is much more complicated and sometimes it is not even single valued
Magnetic Moment resultant from the spin of a single unpaired electron→ Bohr Magneton = 9.273 x 1024 A/m2 ORIGIN OF MAGNETISM IN MATERIALS A moving electric charge, macroscopically or “microscopically” is responsible for Magnetism Nuclear spin Weak effect Unpaired electrons required for net Magnetic Moment Spin of electrons Origin of Magnetism Orbital motion of electrons This effect is
In the solid the outer orbitals of the atoms interact to form Energy bands→ the simple picture used for an atom has to be modified • Teh
Superconducting Diamagnetic
A pole of unit strength is one which exerts a force of one d