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Title: Role of superexchange interactions in the ferromagnetism of manganites

Compound La{sub 0.7}Sr{sub 0.3}Mn{sub 0.85}Nb{sub 0.15}O{sub 3}, in which manganese ions are in an oxidation state close to 3+, are studied by neutron diffraction and magnetic measurements. This compound is shown to be a ferromagnet with T{sub C} = 145 K and a magnetic moment of 3.1 μ{sub B}/Mn at T = 10 K. No signs of cooperative orbital ordering are detected. When Mg{sup 2+} ions substitute for some Nb{sup 5+} ions, Mn{sup 4+} ions appear but ferromagnetism is not enhanced. An increase in the structural distortions leads to a decrease in the ferromagnetic component. The ferromagnetic state is assumed to be caused by substantial hybridization of the e{sub g} orbitals of manganese and oxygen, which increases the positive part of the superexchange interactions.
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. National Academy of Sciences of Belarus, Scientific and Practical Materials Research Centre (Belarus)
  2. Russian Academy of Sciences, Kirensky Institute of Physics, Siberian Branch (Russian Federation)
  3. Helmholtz Center Berlin (Germany)
  4. Joint Institute for Nuclear Research (Russian Federation)
  5. Institut Laue-Langevin (France)
Publication Date:
OSTI Identifier:
22472434
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Experimental and Theoretical Physics; Journal Volume: 120; Journal Issue: 1; Other Information: Copyright (c) 2015 Pleiades Publishing, Inc.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CURIE POINT; EXCHANGE INTERACTIONS; FERROMAGNETIC MATERIALS; FERROMAGNETISM; LANTHANUM COMPOUNDS; MAGNETIC MOMENTS; MANGANATES; MANGANESE IONS; NEUTRON DIFFRACTION; NIOBIUM COMPOUNDS; NIOBIUM IONS; STRONTIUM COMPOUNDS; VALENCE