Magnetic Ceramics Essay

1793 WordsJun 23, 20128 Pages
Magnetic Ceramics Marzia Hoque Tania Introduction  Magnetism is the force of attraction or repulsion of a magnetic material due to the arrangement of its atoms, particularly its electrons.  All magnetic phenomena result from forces between electric charges in motion. Demonstration of the magnetic moment associated with (a) an orbiting electron and (b) a spinning electron. Classifications  There are various types of magnetic material classified by their magnetic susceptibilities: diamagnetic paramagnetic and ferromagnetic/ferrimagnetic. Weak Magnetism Diamagnetism      Induced magnetic dipoles directed reverse to the external magnetic field. Requirements: atoms with completely filled orbitals Magnetic moment: no magnetic moment without applied field compensation of spin moments Permeability / susceptibility: μr< 1 , χm < 0 (weak effect) Materials: inert gases, ionic crystals, semiconductors, Cu, Au, Ag Weak Magnetism: Diamagnetism  direction of magnetic moments (H = 0):  impact on lines of flux in a homogeneous magnetic field: Weak Magnetism: Diamagnetism Weak Magnetism: Diamagnetism Weak Magnetism: Diamagnetism Weak Magnetism Paramagnetism  Alignment of permanent magnetic dipoles in the direction of the external magnetic field.  requirements: atoms with partially filled orbitals  magnetic moment: permanent magnetic moment 0 (weak effect)  materials: Alkali- and transition metals, rare earth metals O2, Al, Sn, Pt Weak Magnetism: Paramagnetism  direction of magnetic moments (H = 0):  impact on lines of flux in a homogeneous magnetic field: Weak Magnetism: Paramagnetism Weak Magnetism: Paramagnetism Weak Magnetism: Paramagnetism Strong Magnetism Ferromagnetism  Spontaneous alignment of all permanent magnetic dipoles within a domain in the crystal lattice

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