Structural, magnetic and electrochemical characterization of La(0.83)A(0.17)Fe(0.5)Cr(0.5)O(3-delta) (A = Ba, Ca) perovskites
Artikel i vetenskaplig tidskrift, 2009
The structural, magnetic and electrical properties of the perovskite-type compound La(0.83)A(0.17)Fe(0.5)Cr(0.5)O(3-delta) (A = Ba, Ca) have been investigated by neutron diffraction, magnetization measurements and conductivity measurements. Rietveld refinement of X-ray and neutron diffraction data shows that the compound adopts an orthorhombic crystal structure with Pbnm symmetry with a random positioning of the iron and chromium cations on the B sublattice. The magnetic structures at 10 K are collinear antiferromagnetic with the magnetic moment per site being equal to 2.91(2)mu(B) (for Ba) and 3.05(2)mu(B) (for Ca). Magnetization measurements confirm the overall antiferromagnetic behavior. The magnetic structure is based Oil a unit cell related to that of the nuclear structure and the magnetic cell can be considered the same as nuclear cell. Barium doped samples show lower oxygen deficiency and higher conductivity than calcium doped samples. At low oxygen pressure, both compounds show p-type electronic conduction. (c) 2009 Elsevier Ltd. All rights reserved.