Short-range Charge and Spin Superstructures in Doped Layered Co Perovskites

Abstract

We have investigated cobaltite relatives of the layered perovskite cuprates and nickelates, Pr${}_{2-x}$Ca${}_x$CoO${}_4$ ($0.39\le x\le 0.73$) and La${}_{2-x}$Sr${}_x$CoO${}_4$ ($x=0.61$), using elastic neutron scattering. We have discovered doping-dependent incommensurate short-range ordering of charges and magnetic moments, which in cobaltites occur in the range of heavy doping, $0.5\lesssim x\lesssim 0.75$. The charge order exists already at room temperature and shows no change on cooling. The incommensurability of its propagation vector, ${\mathbf{Q}}_c=({\epsilon }_c,0,l)$, roughly scales with the concentration of Co${}^{2+}$ ions, ${\epsilon }_c\sim (1-x)$. Magnetic order is only established at low T$\lesssim 40$ K and has twice larger periodicity, indicating a dominant antiferromagnetic correlation between the nearest Co${}^{2+}$ spins.

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References in corpus (8)

• How to detect fluctuating order in the high-temperature superconductors
• Spontaneous rearrangement of the checkerboard charge order to stripe order in La1.5Sr0.5NiO4
• Structural and magnetic properties of the single-layer manganese oxide La{1-x}Sr{1+x}MnO4
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Cited by in corpus (9)

• Spin blockade, orbital occupation and charge ordering in La_(1.5)Sr_(0.5)CoO4
• Stacked Charge Stripes in Quasi-Two_Dimensional Trilayer Nickelate La4Ni3O8
• Neutron scattering studies on stripe phases in non-cuprate materials
• Hour-glass magnetic spectrum in a stripe-less insulating transition metal oxide
• Evidence for a temperature-induced spin-state transition of Co3+ in La2-xSrxCoO4
• Stripes and Superconductivity in Cuprates
• Incommensurate spin correlations in highly oxidized cobaltates La${}_{2-x}$Sr${}_x$CoO${}_4$
• Magnetic phase diagram of La${}_{2-x}$Sr${}_x$CoO${}_4$ revised using muon-spin relaxation
• Evolution of valence-specific spin states and local distortions in La${}_{2-x}$Sr${}_x$CoO${}_4$