Synthesis, crystal chemistry and physical properties of the Ruddlesden-Popper phases Sr{sub 3}Fe{sub 2-x}Ni{sub x}O{sub 7-{delta}} (0=<x=<1.0)

Journal Article · Sun May 15 00:00:00 EDT 2005 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2005.02.018· OSTI ID:20725934

Mogni, Liliana ^[1]; Prado, Fernando ^[1]; Ascolani, Hugo ^[1]; Abbate, Miguel ^[2]; Moreno, Mario S ^[1]; Manthiram, Arumugam ^[3]; Caneiro, Alberto ^[1]

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1. Centro Atomico Bariloche, CNEA, Av. E. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina)
2. Departamento de Fisica, Universidade Federal do Parana, Caixa Postal 19091, 81531-990 Curitiba PR (Brazil)
3. Materials Science and Engineering Program, University of Texas at Austin, Austin, TX 78712 (United States)

The crystal chemistry, electronic structure, and electrical and magnetic properties of the novel perovskite-related nickel oxides Sr{sub 3}Fe{sub 2-x}Ni{sub x}O{sub 7-{delta}} with 0=<x=<1.0 have been studied. X-ray diffraction and selected area electron diffraction (ED) data indicate that the samples have a tetragonal (Space group I4/mmm) structure. ED patterns and high-resolution images reveal the presence of a regular stacking along the c-axis for the x=1.0 sample. The lattice parameters, oxygen content, and average oxidation state of iron and nickel decrease with increasing Ni content. The electronic structure of the x=1.0 sample was studied by M 2p X-ray photoelectron spectroscopy (XPS). An analysis of the spectra using the cluster model indicates that this material is in the negative charge-transfer regime and the ground state is dominated by the 3d{sup n+1}L configuration with 2p holes (L) in the oxygen band. The insulator states are stabilized due to a p-p type band gap that arises because the p-d transfer integral T{sub {sigma}} dominates over the O 2p bandwith. Although magnetic measurements reveal the presence of ferromagnetic interactions that lead to magnetic frustration at T=<40K, no long-range magnetic order was observed for the samples with x>=0.3. The electrical resistivity decreases with increasing Ni content as the p-p band gap tend to close due to the reduction of the T{sub {sigma}} value. Negative magnetoresistance ({approx}-24% for x=0.6 and -7% for x=1.0 at 20K and 9T) was observed for the Ni containing samples.

• OSTI ID: 20725934
• Journal Information: Journal of Solid State Chemistry, Vol. 178, Issue 5; Other Information: DOI: 10.1016/j.jssc.2005.02.018; PII: S0022-4596(05)00079-4; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CLUSTER MODEL
CRYSTALS
ELECTRON DIFFRACTION
ELECTRONIC STRUCTURE
IRON COMPOUNDS
LATTICE PARAMETERS
MAGNETIC PROPERTIES
MAGNETORESISTANCE
NICKEL OXIDES
PEROVSKITE
SPACE GROUPS
STRONTIUM COMPOUNDS
TETRAGONAL LATTICES
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY