Module 2 : Systems under technological importance

Lecture 12 : Inorganic semiconductors -Magnetic materials - 2

 

  • Ferromagnetic Cr chalcogenide spinels
    CdCr2 S4 , CdCr2 Se4 (Tc = 129 K)
  • Manganites
    (La,X)MnO3 , …
    structure: based on perovskite, tilted
Mechanism: double exchange, due to
mixed valence Mn3+Mn4+ $ Mn4+Mn3+

 

 

Very complicated (i.e. interesting) system! Many types of magnetic order, stripe phases, orbital order, metal-insulator transitions, colossal magnetoresistance…See Salamon & Jaime, RMP 73, 583 (2001)