title: New Fe3+/Cr3+ perovskites with anomalous transport properties: the solid solution La(x)Bi(1-x)Fe(0.5)Cr(0.5)O3 (0.4 ≤ x ≤ 1).
abstract: In this work, the sol-gel synthesis, structural characterization, and transport properties of a new solid solution of the general formula La(x)Bi(1-x)Fe(0.5)Cr(0.5)O(3) (0.4 ≤ x ≤ 1) are presented. The solubility limit x has been determined and variation of the lattice parameters measured through profile fitting. The cell parameters, space group, and atomic positions, as obtained by the Rietveld refinement of X-ray diffraction data, are reported. This analysis and electron diffraction studies as well do not reveal any evidence of Fe/Cr ordering. Regarding the transport properties, magnetic and electric characterizations are described. The electrical response with the temperature and frequency has been studied, and a "positive temperature coefficient" for the resistivity has been found for temperatures between 270 and 400 °C. The magnetic behavior is striking because, for all materials studied, zero-field-cooling curves appear above field-cooling ones, an anomalous feature that is interpreted as being due to complex ferromagnetic/antiferromagnetic interactions in the B perovskite sublattice.
authors.affiliation: Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, AP 70360 México DF 04510, México.
authors.forename: M E
authors.initials: ME
authors.lastname: Villafuerte-Castrejón
authors.forename: M
authors.initials: M
authors.lastname: García-Guaderrama
authors.forename: L
authors.initials: L
authors.lastname: Fuentes
authors.forename: J
authors.initials: J
authors.lastname: Prado-Gonjal
authors.forename: A M
authors.initials: AM
authors.lastname: González
authors.forename: M Á
authors.initials: MÁ
authors.lastname: de la Rubia
authors.forename: M
authors.initials: M
authors.lastname: García-Hernández
authors.forename: E
authors.initials: E
authors.lastname: Morán