X-ray and neutron scattering

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Observation of 3D Heisenberg-like ferromagnetism in single crystal La_{0.875}Sr_{0.125}MnO_3

(2003)

Authors:

Sunil Nair, A Banerjee, AV Narlikar, D Prabhakaran, AT Boothroyd
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Soft X-ray resonant magnetic diffraction.

Phys Rev Lett 90:18 (2003) 187201

Authors:

SB Wilkins, PD Hatton, MD Roper, D Prabhakaran, AT Boothroyd

Abstract:

We have conducted the first soft x-ray diffraction experiments from a bulk single crystal, studying the bilayer manganite La2-2xSr1+2xMn2O7 with x=0.475 in which we were able to access the (002) Bragg reflection using soft x rays. The Bragg reflection displays a strong resonant enhancement at the L(III) and L(II) manganese absorption edges. We demonstrate that the resonant enhancement of the magnetic diffraction of the (001) is extremely large, indeed so large that it exceeds that of the nonresonant Bragg diffraction. Resonant soft x-ray scattering of 3d transition metal oxides is the only technique for the atomic selective measurement of spin, charge, and orbital correlations in materials, such as high temperature superconductors, colossal magnetoresistance manganites, and charge stripe nickelates.
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Erratum: Observation of the dynamical structure arising from spatially extended quantum entanglement and long-lived quantum coherence in the KHCO3 crystal (Physical Review B - Condensed Matter and Materials Physics (2003) 67 (54301))

Physical Review B - Condensed Matter and Materials Physics 67:18 (2003) 1899011

Authors:

F Fillaux, A Cousson, D Keen

Spin dynamics in stripe-ordered La5/3Sr1/3NiO4

Physical Review B Condensed Matter and Materials Physics 67:10 (2003) 1004071-1004074

Authors:

AT Boothroyd, D Prabhakaran, PG Freeman, SJS Liste, M Enderle, A Hiess, J Kulda

Abstract:

Polarized- and unpolarized-neutron inelastic scattering has been used to measure the spin excitations in the striped spin-charge-ordered phase of La5/3Sr1/3NiO4. Above 30 meV, sharp magnetic modes are observed characteristic of a static stripe lattice. This part of the energy spectrum is described well by a linear spin-wave model with intrastripe and interstripe exchange interactions between neighboring Ni spins given by J = 15 ±1.5 meV and J′ = 7.5±1.5 meV, respectively. A pronounced suppression and broadening of the magnetic fluctuations in a band between 10 meV and 25 meV is suggestive of coupling to collective motions of the stripe domain walls.
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Preparation of large single crystals ANb(2)O(6) (A = Ni, Co, Fe, Mn) by the floating-zone method

J CRYST GROWTH 250:1-2 (2003) 72-76

Authors:

D Prabhakaran, FR Wondre, AT Boothroyd

Abstract:

Single crystals of ANb(2)O(6) (A = Nil Co, Fe, Mn) niobates have been grown by the floating-zone technique for the first time. The crystals were melt-grown from stoichiometric mixtures of the starting oxides. The orientation of the crystallographic axes relative to the crystal rod axis was found to be influenced by the size of the molten zone. Magnetization measurements as a function of temperature and applied field show that the magnetic properties are consistent with those found in previous studies. (C) 2002 Elsevier Science B.V. All rights reserved.
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