title: Ferromagnetic Cu-O-Cu coupling in CaCu3Sn4O12 probed by neutron diffraction.
abstract: The A-site ordered perovskite oxide with the formula CaCu(3)Sn(4)O(12) has been synthesized in polycrystalline form under moderate pressure conditions (3.5 GPa) in combination with high temperature (1000 °C). This oxide crystallizes in the cubic space group [Formula: see text] (no. 204) with the unit-cell parameter a = 7.64535(6) Å at 300 K. The SnO(6) network is extremely tilted, giving rise to a square planar coordination for Cu(2+) cations. The non-magnetic character of Sn(4+) offers an excellent opportunity to probe the magnetism of Cu(2+) at the A sublattice in CaCu(3)Sn(4)O(12). Magnetic susceptibility shows that this compound is ferromagnetic below T(C) = 10 K, which is an unusual magnetic behaviour in cuprates. This peculiar aspect has been examined by neutron powder diffraction. The refinement of the magnetic structure at 4 K indeed indicates a parallel coupling between Cu(2+) spins with a magnetic moment of 0.5 μ(B)/Cu atom.
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco E-28049 Madrid, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Kayser
authors.forename: M
authors.initials: M
authors.lastname: Retuerto
authors.forename: J
authors.initials: J
authors.lastname: Sánchez-Benítez
authors.forename: M J
authors.initials: MJ
authors.lastname: Martínez-Lope
authors.forename: M T
authors.initials: MT
authors.lastname: Fernández-Díaz
authors.forename: J A
authors.initials: JA
authors.lastname: Alonso
mesh_terms: D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D060328:Magnetic Phenomena; D008958:Models, Molecular; D008968:Molecular Conformation; D033363:Neutron Diffraction; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D017971:Tin Compounds / Q000737:chemistry*
chemical_list: D010087:Oxides; D017971:Tin Compounds; D003300:Copper; D010100:Oxygen