Cooperative ordering of holes and spins in La{sub 2}NiO{sub 4.125}
- Physics Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)
- Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716 (United States)
La{sub 2}NiO{sub 4.125} exhibits a cooperative ordering of dopant-induced holes and Ni spins below a transition temperature of 110 K. There is also an ordering of interstitial oxygens that occurs near room temperature. We present a comprehensive analysis of experimentally observed superlattice intensities in terms of structural models, justifying previous identifications. The model for the interstitial order involves a 3{bold a}{times}5{bold b}{times}5{bold c} unit cell with an ideal interstitial density of {delta}=2/15 per formula unit. In the spin and charge ordered state, the magnetic moments are sinusoidally modulated within the NiO{sub 2} planes. The moments point transverse to the modulation direction, with nearest neighbors antiparallel, and have a maximum amplitude that is {gt}80% of that observed in undoped La{sub 2}NiO{sub 4}. A corresponding modulation of atomic positions within NiO{sub 2} planes involves breathing-mode distortions consistent with a modulation of the charge density. The results are compared with theoretical models and with experimental observations on related systems.
- Research Organization:
- Brookhaven National Laboratory
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 91898
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 5 Vol. 52; ISSN 0163-1829; ISSN PRBMDO
- Country of Publication:
- United States
- Language:
- English
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