Left for b 0 the electrons with spin up and down have

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Unformatted text preview: ectron: (7.26) ⇒ µz = ±µB (only spin, no orbital angular momentum) (7.38) Fig. 7.10 Pauli paramagnetism at about absolute zero for free electrons. (Left) for B = 0 the electrons with spin up and down have the same energy. (Middle) for B ≠ 0 there is a shift of 2µBB between the electrons of spin up and down. (Left) The numbers of electrons in the ″up″ and ″down″ band will adjust to achive an equal Fermi level (chemical potential). This leads to an excess of moment up electrons in the magnetic field and hence to a net magnetic moment of the conduction electrons. Note that the figure is out of scale. At B = 5T the energy shift is 2µBB ≈ 6×10-4 eV << EF. Therefore, the shift of the Fermi level can be neglected in the calculation: EF ≈EF (B = 0). Mz = (n+ - n-)µB n± : density of electrons with spin up and down 2 ⇒ χ Pauli ≈ µ B D ( E F ) µ 0 (7.39) (7.40) (derivation see practical course) EF(T) ≈ const. in metals ⇒ χPauli(T) ≈ const ! 7-17 Landau diamagnetism of conduction electrons B-field ⇒ ″condensation″ of conduction electrons on landau tubes: orbits ⊥ B ...
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This note was uploaded on 01/19/2010 for the course MATERIALS M504 taught by Professor Adelung during the Spring '02 term at Uni Kiel.

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