Spectacular Effect of Doping upon Magnetism and Conductivity in Manganites
Manganites are very sensitive to the presence of impurities on the Mn sites of the perovskite structure. In this respect, the doping of orbital-charge ordered manganites, such as Ln0.5Ca0.5MnO3 or Ln0.4Ca0.6MnO3 by various elements is spectacular. Starting from the antiferromagnetic CE-type insulator, two classes of materials can be generated, depending on the nature of the dopant : for non magnetic elements (Al, Ga, Ti, Sn, In, Sc, Mg) and iron, spin glass insulators are obtained whereas for magnetic cations (Cr, Co, Ni, Cu, Rh, Ir, Ru), metallic ferromagnets are generated. As a consequence, the doping at Mn sites modifies dramatically the magnetic phase diagrams of the manganites, even for the LaMnO3 phase alone which by doping with varioius cations (Zn, Li, Mg, Co, Ni) becomes ferromagnetic, due to valency effects.
Presentation: invited oral at E-MRS Fall Meeting 2003, Symposium D, by Bernard RAVEAU
See On-line Journal of E-MRS Fall Meeting 2003
Submitted: 2003-05-26 14:34 Revised: 2009-06-08 12:55